251
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Zhou Y, Yuan J, Wu J, Han X. The toxic effects of microcystin-LR on rat spermatogonia in vitro. Toxicol Lett 2012; 212:48-56. [DOI: 10.1016/j.toxlet.2012.05.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/27/2012] [Accepted: 05/01/2012] [Indexed: 01/22/2023]
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252
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Stewart I, Eaglesham GK, McGregor GB, Chong R, Seawright AA, Wickramasinghe WA, Sadler R, Hunt L, Graham G. First report of a toxic Nodularia spumigena (Nostocales/ Cyanobacteria) bloom in sub-tropical Australia. II. Bioaccumulation of nodularin in isolated populations of mullet (Mugilidae). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2012; 9:2412-43. [PMID: 22851952 PMCID: PMC3407913 DOI: 10.3390/ijerph9072412] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 06/19/2012] [Accepted: 06/20/2012] [Indexed: 12/03/2022]
Abstract
Fish collected after a mass mortality at an artificial lake in south-east Queensland, Australia, were examined for the presence of nodularin as the lake had earlier been affected by a Nodularia bloom. Methanol extracts of muscle, liver, peritoneal and stomach contents were analysed by HPLC and tandem mass spectrometry; histological examination was conducted on livers from captured mullet. Livers of sea mullet (Mugil cephalus) involved in the fish kill contained high concentrations of nodularin (median 43.6 mg/kg, range 40.8-47.8 mg/kg dry weight; n = 3) and the toxin was also present in muscle tissue (median 44.0 μg/kg, range 32.3-56.8 μg/kg dry weight). Livers of fish occupying higher trophic levels accumulated much lower concentrations. Mullet captured from the lake 10 months later were also found to have high hepatic nodularin levels. DNA sequencing of mullet specimens revealed two species inhabiting the study lake: M. cephalus and an unidentified mugilid. The two mullet species appear to differ in their exposure and/or uptake of nodularin, with M. cephalus demonstrating higher tissue concentrations. The feeding ecology of mullet would appear to explain the unusual capacity of these fish to concentrate nodularin in their livers; these findings may have public health implications for mullet fisheries and aquaculture production where toxic cyanobacteria blooms affect source waters. This report incorporates a systematic review of the literature on nodularin measured in edible fish, shellfish and crustaceans.
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Affiliation(s)
- Ian Stewart
- Queensland Health Forensic and Scientific Services, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia; (G.K.E.); (L.H.); (G.G.)
- School of Public Health, Griffith University, Parklands Drive, Southport, Queensland 4217, Australia;
| | - Geoffrey K. Eaglesham
- Queensland Health Forensic and Scientific Services, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia; (G.K.E.); (L.H.); (G.G.)
| | - Glenn B. McGregor
- Environment and Resource Sciences, Queensland Department of Science, Information Technology, Innovation and the Arts, Ecosciences Precinct, Boggo Road, Dutton Park, Queensland 4102, Australia;
| | - Roger Chong
- Biosecurity Queensland, Department of Agriculture, Fisheries and Forestry, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia;
| | - Alan A. Seawright
- The University of Queensland, National Research Centre for Environmental Toxicology (EnTox), 39 Kessels Road, Coopers Plains, Queensland 4108, Australia; (A.A.S.); (W.A.W.)
| | - Wasantha A. Wickramasinghe
- The University of Queensland, National Research Centre for Environmental Toxicology (EnTox), 39 Kessels Road, Coopers Plains, Queensland 4108, Australia; (A.A.S.); (W.A.W.)
| | - Ross Sadler
- School of Public Health, Griffith University, Parklands Drive, Southport, Queensland 4217, Australia;
| | - Lindsay Hunt
- Queensland Health Forensic and Scientific Services, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia; (G.K.E.); (L.H.); (G.G.)
| | - Glenn Graham
- Queensland Health Forensic and Scientific Services, 39 Kessels Road, Coopers Plains, Queensland 4108, Australia; (G.K.E.); (L.H.); (G.G.)
- Faculty of Science, Health and Education, University of the Sunshine Coast, Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
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253
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Cantor GH, Beckonert O, Bollard ME, Keun HC, Ebbels TMD, Antti H, Wijsman JA, Bible RH, Breau AP, Cockerell GL, Holmes E, Lindon JC, Nicholson JK. Integrated Histopathological and Urinary Metabonomic Investigation of the Pathogenesis of Microcystin-LR Toxicosis. Vet Pathol 2012; 50:159-71. [DOI: 10.1177/0300985812443839] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Patterns of change of endogenous metabolites may closely reflect systemic and organ-specific toxic changes. The authors examined the metabolic effects of the cyanobacterial (blue-green algal) toxin microcystin-LR by 1H-nuclear magnetic resonance (NMR) analysis of urinary endogenous metabolites. Rats were treated with a single sublethal dose, either 20 or 80 µg/kg intraperitoneally, and sacrificed at 2 or 7 days post dosing. Changes in the high-dose, 2-day sacrifice group included centrilobular hepatic necrosis and congestion, accompanied in some animals by regeneration and neovascularization. By 7 days, animals had recovered, the necrotizing process had ended, and the centrilobular areas had been replaced by regenerative, usually hypertrophic hepatocytes. There was considerable interanimal variation in the histologic process and severity, which correlated with the changes in patterns of endogenous metabolites in the urine, thus providing additional validation of the biomarker and biochemical changes. Similarity of the shape of the metabolic trajectories suggests that the mechanisms of toxic effects and recovery are similar among the individual animals, albeit that the magnitude and timing are different for the individual animals. Initial decreases in urinary citrate, 2-oxoglutarate, succinate, and hippurate concentrations were accompanied by a temporary increase in betaine and taurine, then creatine from 24 to 48 hours. Further changes were an increase in guanidinoacetate, dimethylglycine, urocanic acid, and bile acids. As a tool, urine can be repeatedly and noninvasively sampled and metabonomics utilized to study the onset and recovery after toxicity, thus identifying time points of maximal effect. This can help to employ histopathological examination in a guided and effective fashion.
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Affiliation(s)
- G. H. Cantor
- Discovery Toxicology, Bristol-Myers Squibb Co., Princeton, NJ, USA
| | - O. Beckonert
- Department of Surgery and Cancer, Biomolecular Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
| | - M. E. Bollard
- Department of Surgery and Cancer, Biomolecular Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
| | - H. C. Keun
- Department of Surgery and Cancer, Biomolecular Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
| | - T. M. D. Ebbels
- Department of Surgery and Cancer, Biomolecular Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
| | - H. Antti
- Department of Chemistry, Umeå, Sweden
| | | | - R. H. Bible
- Global Drug Metabolism, Pharmacia Corp., Skokie IL, USA
- Deceased
| | - A. P. Breau
- Biologics Development Services, Sarasota, FL, USA
| | | | - E. Holmes
- Department of Surgery and Cancer, Biomolecular Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
| | - J. C. Lindon
- Department of Surgery and Cancer, Biomolecular Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
| | - J. K. Nicholson
- Department of Surgery and Cancer, Biomolecular Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
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254
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Papadimitriou T, Kagalou I, Stalikas C, Pilidis G, Leonardos ID. Assessment of microcystin distribution and biomagnification in tissues of aquatic food web compartments from a shallow lake and evaluation of potential risks to public health. ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:1155-1166. [PMID: 22383140 DOI: 10.1007/s10646-012-0870-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/09/2012] [Indexed: 05/31/2023]
Abstract
The objectives of this study were: (1) to examine the distribution and bioaccumulation of microcystins in the main components of the food web (phytoplankton, zooplankton, crayfish, shrimp, mussel, snail, fish, frog) of Lake Pamvotis (NW Greece), (2) to investigate the possibility of microcystin biomagnification and (3) to evaluate the potential threat of the contaminated aquatic organisms to human health. Significant microcystin concentrations were detected in all the aquatic organisms during two different periods, with the higher concentrations observed in phytoplankton and the lower in fish species and frogs. This is the first study reporting microcystin accumulation in the body of the freshwater shrimp Atyaephyra desmsaresti, in the brain of the fish species common carp (Cyprinus carpio) and in the skin of the frog Rana epirotica. Although there was no evidence for microcystin biomagnification, the fact that microcystins were found in lake water and in the tissues of aquatic organisms, suggests that serious risks to animal and public health are possible to occur. In addition, it is likely to be unsafe to consume aquatic species harvested in Lake Pamvotis due to the high-concentrations of accumulated microcystins.
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Affiliation(s)
- Theodoti Papadimitriou
- Biological Applications and Technology Department, University of Ioannina, Ioannina, Greece
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255
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Lowe J, Souza-Menezes J, Freire D, Mattos L, Castiglione R, Barbosa C, Santiago L, Ferrão F, Cardoso L, da Silva R, Vieira-Beiral H, Vieyra A, Morales M, Azevedo S, Soares R. Single sublethal dose of microcystin-LR is responsible for different alterations in biochemical, histological and physiological renal parameters. Toxicon 2012; 59:601-9. [DOI: 10.1016/j.toxicon.2012.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 02/02/2012] [Accepted: 02/07/2012] [Indexed: 11/25/2022]
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256
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Jiang J, Shi Y, Shan Z, Yang L, Wang X, Shi L. Bioaccumulation, oxidative stress and HSP70 expression in Cyprinus carpio L. exposed to microcystin-LR under laboratory conditions. Comp Biochem Physiol C Toxicol Pharmacol 2012; 155:483-90. [PMID: 22240489 DOI: 10.1016/j.cbpc.2011.12.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 12/20/2011] [Accepted: 12/20/2011] [Indexed: 11/28/2022]
Abstract
Microcystin-LR (MC-LR) produced by cyanobacteria are potent specific hepatotoxins. So far the pathogenesis of environmental MC-LR toxicity to aquatic organisms has not been fully elucidated. In the present study the accumulation of MC-LR was investigated in various organs/tissues of Cyprinus carpio L. (C. carpio) following exposure to MC-LR for 14 d at environmentally relevant concentrations (0.1 to 10 μg L(-1)). Results showed that the presence of MC-LR enhanced toxin accumulation in all investigated organs and the highest accumulation was found in the liver of fish exposed to 5.0 μg L(-1) of MC-LR. An EPR analysis indicated ·OH intensity in liver was significantly induced at 0.1 μg L(-1) of MC-LR and then restored when the MC-LR concentration was greater than 0.1 μg L(-1). After 14-day exposure, MC-LR (1.0-10.0 μg L(-1) of MC-LR) caused a pronounced promotion of glutathione S-transferase (GST) activity and a depletion of reduced glutathione (GSH) content in fish liver, which indicated that GSH was involved in detoxification of MC-LR and the conjugation reaction of MC-LR and GSH occurred. A mild oxidative damage was evidenced by the accumulation of malondialdehyde (MDA) level at 5.0 μg L(-1) of MC-LR exposure, but which was restored when the MC-LR concentration was increased to 10.0 μg L(-1). The responses of antioxidant enzymes and the induction of HSP70 expression might contribute to MC-LR tolerance of C. carpio. However, the protein phosphatase (PP) activities were strikingly inhibited in all treated groups. Thus, the overall toxicity of environmental MC-LR on C. carpio seems to be initiated in the liver via both the ROS pathway and the PP inhibition pathway, and the latter might be more important when ambient MC-LR concentration is greater than 0.1 μg L(-1). More importantly, these results can help to support the evaluation on the potential effects of MC-LR under common environmental concentrations.
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Affiliation(s)
- Jinlin Jiang
- Nanjing Institute of Environmental Sciences, Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection, Nanjing 210042, PR China
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257
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Gonçalves-Soares D, Zanette J, Yunes JS, Yepiz-Plascencia GM, Bainy ACD. Expression and activity of glutathione S-transferases and catalase in the shrimp Litopenaeus vannamei inoculated with a toxic Microcystis aeruginosa strain. MARINE ENVIRONMENTAL RESEARCH 2012; 75:54-61. [PMID: 21889198 DOI: 10.1016/j.marenvres.2011.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 07/23/2011] [Accepted: 07/27/2011] [Indexed: 05/21/2023]
Abstract
Microcystin (MC) produced during cyanobacteria blooms is notably toxic to human and wildlife. Conjugation with reduced glutathione (GSH) by glutathione S-transferase (GST) and the antioxidant enzymes defenses (e.g. catalase, CAT) are important biochemical defense mechanisms against MCs toxicity. We investigated the enzymatic activity of CAT and GST and the gene expression levels of CAT and eight GST isoforms in the hepatopancreas of the globally farmed shrimp Litopenaeus vannamei 48-h after injection with a sub-lethal dose of 100 μg kg⁻¹ of a toxic Microcystis aeruginosa extract. MCs caused up-regulation for GSTΩ, μ and a MAPEG isoform, by 12-, 2.8- and 1.8-fold, respectively, and increases in the total GST enzyme activity and CAT enzyme activity. The study points to the importance of further characterization for the L. vannamei GST isoforms and GST/CAT post-translational regulation processes to better understand the key mechanisms involved in the shrimp's defense against MC exposure.
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Affiliation(s)
- Daniela Gonçalves-Soares
- Departamento de Bioquímica, Núcleo de Estudos em Patologia Aquícola, Universidade Federal de Santa Catarina, Servidão Caminho do Porto, s/n, Itacorubi, Florianópolis, SC 88034-257, Brazil
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258
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Lezcano N, Sedán D, Lucotti I, Giannuzzi L, Vittone L, Andrinolo D, Mundiña-Weilenmann C. Subchronic microcystin-lr exposure increased hepatic apoptosis and induced compensatory mechanisms in mice. J Biochem Mol Toxicol 2012; 26:131-8. [DOI: 10.1002/jbt.20419] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/20/2011] [Accepted: 11/04/2011] [Indexed: 01/19/2023]
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259
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Zhang Z, Zhang XX, Qin W, Xu L, Wang T, Cheng S, Yang L. Effects of microcystin-LR exposure on matrix metalloproteinase-2/-9 expression and cancer cell migration. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2012; 77:88-93. [PMID: 22088328 DOI: 10.1016/j.ecoenv.2011.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 10/21/2011] [Accepted: 10/25/2011] [Indexed: 05/31/2023]
Abstract
This study assessed the effects of microcystin-LR (MC-LR) exposure on matrix metalloproteinases (MMPs) expression and cancer cell migration. After male mice were orally administered with different concentrations of MC-LR for 270 d, histopathologic observation revealed an obvious hepatic lymphocyte infiltration or fatty degeneration. Immunohistochemical staining and enzyme-linked immunosorbent assay demonstrated that MC-LR treatment (even at 1 nM) caused up-regulated expressions of hepatic MMP-2/-9. Quantitative reverse-transcriptase PCR showed that the exposure to 80 nM MC-LR induced an increase of MMP-2/-9 mRNA levels by 1.0 and 1.9 fold. Breast cancer cells (MDA-MB-435s) were also cultured with MC-LR solutions and a wound healing assay demonstrated that MC-LR posed a time/dose-dependent stimulation effect on migration of the cancer cells. Gelatin electrophoresis and quantitative PCR showed significant increases in cellular MMP-2/-9 expressions after MC-LR exposure. This study indicated that chronic exposure to MC-LR could alter MMP-2/-9 expressions and stimulate cancer cell migration.
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Affiliation(s)
- Zongyao Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, China
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260
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Moutou KA, Tsikogias S, Papadimitriou T, Kagalou I. Oxidative stress in Cyprinus carpio to analyze microcystin impact in eutrophic shallow lakes: a preliminary study. ACTA ACUST UNITED AC 2012; 14:2195-203. [DOI: 10.1039/c2em30129f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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261
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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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262
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Fardel O, Kolasa E, Le Vee M. Environmental chemicals as substrates, inhibitors or inducers of drug transporters: implication for toxicokinetics, toxicity and pharmacokinetics. Expert Opin Drug Metab Toxicol 2011; 8:29-46. [DOI: 10.1517/17425255.2012.637918] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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263
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Gélinas M, Juneau P, Gagné F. Early biochemical effects of Microcystis aeruginosa extracts on juvenile rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol B Biochem Mol Biol 2011; 161:261-7. [PMID: 22178707 DOI: 10.1016/j.cbpb.2011.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 12/02/2011] [Accepted: 12/05/2011] [Indexed: 11/29/2022]
Abstract
Microcystins (MC) are usually the predominant cyanotoxins associated with cyanobacterial blooms in natural surface waters. These toxins are well-known hepatotoxic agents that proceed by inhibiting protein phosphatase in aquatic biota; recent studies have also reported oxidative stress and disruption of ion regulation in aquatic organisms. In the present study, young trout (Oncorhynchus mykiss) were exposed to crude extracts of Microsystis aeruginosa for four days at 15 °C. The level of microcystins was calculated to confirm the presence of toxins in these crude extracts: 0, 0.75, 1.8 and 5 μg/L. Protein phosphatase measured in the liver increased by at least 3-fold and is significantly as a result of exposure to these sublethal concentrations of crude extract, his indicates an early defense response against protein phosphatase inhibition from cyanotoxins. This was corroborated by the decreased phosphate content in proteins found in the liver and brain. No increase in glutathione-S transferase (GST) activity was observed and lipid peroxidation was unaffected in both liver and brain tissue exposed to the cyanobacterial extracts. The data revealed that the proportion of the reduced (metal-binding) form of metallothionein (MT) decreased by two-fold relative to the control group (with a concomitant increase in the proportion of the oxidized form). The level of phosphate associated with MT increased by 1.5-fold at the highest concentration of crude extract. Acetylcholinesterase (AChE) activity in brain tissue was decreased after exposure to the highest concentration of crude extract, suggesting a slowdown in neural activity. However, no biotransformation processes or detoxification of GST was triggered. Our findings show early sign of biochemical effects of MC-LR in young trout.
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Affiliation(s)
- Malorie Gélinas
- Environment Canada, 105 McGill Street, Montréal, Quebec, Canada H2Y 2E7.
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264
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Meng G, Sun Y, Fu W, Guo Z, Xu L. Microcystin-LR induces cytoskeleton system reorganization through hyperphosphorylation of tau and HSP27 via PP2A inhibition and subsequent activation of the p38 MAPK signaling pathway in neuroendocrine (PC12) cells. Toxicology 2011; 290:218-29. [DOI: 10.1016/j.tox.2011.09.085] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Revised: 09/23/2011] [Accepted: 09/28/2011] [Indexed: 11/16/2022]
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265
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Iusuf D, van de Steeg E, Schinkel AH. Functions of OATP1A and 1B transporters in vivo: insights from mouse models. Trends Pharmacol Sci 2011; 33:100-8. [PMID: 22130008 DOI: 10.1016/j.tips.2011.10.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/12/2011] [Accepted: 10/14/2011] [Indexed: 01/16/2023]
Abstract
Organic anion-transporting polypeptides (OATPs) are a superfamily of uptake transporters that mediate the cellular uptake of a broad range of endogenous and exogenous compounds. Of these OATP transporters, members of the 1A and 1B subfamilies have broad substrate specificities. Because they are mainly expressed in liver, kidney and small intestine, OATP1A and 1B transporters can have a major impact on the pharmacokinetics of many drugs. To study their role in physiology and drug disposition, several mouse models lacking functional expression of one or more OATPs have been generated. This review discusses recent findings for these models that have led to new insights into the impact of OATP1A and 1B transporters on pharmacokinetics and toxicokinetics, and on bilirubin detoxification and bile acid handling in normal liver physiology.
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Affiliation(s)
- Dilek Iusuf
- Division of Molecular Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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266
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Huang P, Zheng Q, Xu LH. The apoptotic effect of oral administration of microcystin-RR on mice liver. ENVIRONMENTAL TOXICOLOGY 2011; 26:443-452. [PMID: 20196164 DOI: 10.1002/tox.20570] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 01/04/2010] [Accepted: 01/11/2010] [Indexed: 05/28/2023]
Abstract
Microcystin produced by cyanobacteria in diverse water systems is a potent hepatotoxin that has been documented to induce hepatocyte apoptosis and liver injury. There are more than eighty reported microcystins. The present work aimed at investigating the apoptotic effect of MC-RR (a common member of microcystin family), and its related mechanism. MC-RR was administered orally to ICR mice for 7 days with different dosages. Apoptotic cell death in liver was detected by TUNEL assay, and the expression levels of Bcl-2, Bax and p53, GRP 78 and CHOP which have been reported to be related to apoptosis and ER stress were determined via western-blot. The activity of PP2A was measured using the serine-threonine phosphatase assay system and PP2A A subunit expression at both transcription and protein levels was measured by RT-PCR and western blot, respectively. A significant difference was observed on the number of TUNEL positive liver cells between the control and MC-RR-treated groups. The expression levels of Bcl-2, Bax, p53, and GRP 78 in MC-RR-treated groups were altered significantly compared to the control, but no obvious alteration was found in CHOP expression. The PP2A activity and A subunit expression did not manifest any obvious change at both transcription and protein levels. The results indicated that oral exposure to MC-RR can cause apoptosis as well as moderate ER stress in mice liver. The mitochondrial pathway via Bcl-2 family members may contribute to the apoptosis. However, PP2A may not be involved in the regulation of apoptotic process under the current conditions.
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Affiliation(s)
- Pu Huang
- Department of Biochemistry and Genetics, School of Medicine, Zhejiang University, Hangzhou 310058, China
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267
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Santos PVF, Lopes IC, Diculescu VC, de Araújo MCU, Oliveira-Brett AM. Redox Mechanisms of Nodularin and Chemically Degraded Nodularin. ELECTROANAL 2011. [DOI: 10.1002/elan.201100246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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268
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Feurstein D, Stemmer K, Kleinteich J, Speicher T, Dietrich DR. Microcystin congener- and concentration-dependent induction of murine neuron apoptosis and neurite degeneration. Toxicol Sci 2011; 124:424-31. [PMID: 21934130 DOI: 10.1093/toxsci/kfr243] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cyanobacterial microcystins (MCs) represent a toxin group with > 100 variants, requiring active uptake into cells via organic anion-transporting polypeptides, in order to irreversibly inhibit serine/threonine-specific protein phosphatases. MCs are a human health hazard with repeated occurrences of severe poisonings. In the well-known human MC intoxication in Caruaru, Brazil (1996), patients developed signs of acute neurotoxicity, e.g., deafness, tinnitus, and intermittent blindness, as well as subsequent hepatotoxicity. The latter data, in conjunction with some animal studies, suggest that MCs are potent neurotoxins. However, there is little data to date demonstrating MC neuron-specific toxicity. MC exposure-induced cytotoxicity, caspase activity, chromatin condensation, and microtubule-associated Tau protein hyperphosphorylation (epitopes serine199/202 and serine396) were determined. Neurite degeneration was analyzed with confocal microscopy and neurite length determined using image analysis. MC-induced apoptosis was significantly increased by MC-LF and MC-LW, however, only at high concentrations (≥ 3μM), whereas significant neurite degeneration was already observed at 0.5μM MC-LF. Moreover, sustained hyperphosphorylation of Tau was observed with all MC congeners. The concentration- and congener-dependent mechanisms observed suggest that low concentrations of MC-LF and MC-LW can induce subtle neurodegenerative effects, reminiscent of Alzheimer's disease type human tauopathies, and thus should be taken more seriously with regard to potential human health effects than the apical cytotoxicity (apoptosis or necrosis) demonstrated at high MC concentrations.
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Affiliation(s)
- Daniel Feurstein
- Human and Environmental Toxicology, University of Konstanz, 78467 Konstanz, Germany.
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269
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Amado LL, Garcia ML, Pereira TCB, Yunes JS, Bogo MR, Monserrat JM. Chemoprotection of lipoic acid against microcystin-induced toxicosis in common carp (Cyprinus carpio, Cyprinidae). Comp Biochem Physiol C Toxicol Pharmacol 2011; 154:146-53. [PMID: 21586338 DOI: 10.1016/j.cbpc.2011.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 04/26/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
Abstract
This paper evaluated the chemoprotective effect of lipoic acid (LA) against microcystin (MC) toxicity in carp Cyprinus carpio. To determine the LA dose and the time necessary for the induction of three different classes (alpha, mu and pi) of glutathione S-transferase (GST) gene transcription, carp were i.p. injected with 40mg/kg lipoic acid solution. A group was killed 24h after the first i.p. injection (condition 1); another group received two i.p. injections with a 24h of interval between each one and was killed 48h after the first injection (condition 2) and a third group received one i.p. injection and was killed 48h latter (condition 3). Results showed that LA was effective in promoting an increase in GSTs gene transcription in liver only in the condition 2. A second experiment was done, where carp pre-treated with LA (condition 2) were gavaged twice with a 24h interval with 50μg MC/kg. Ninety-six hours after experiment beginning, carp were killed, and organs were dissected. Results of GST activity in liver and brain suggest that LA can be a useful chemoprotection agent against MC induced toxicity, stimulating detoxification through the increment of GST activity (brain) or through reversion of GST inhibition (liver).
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Affiliation(s)
- Lílian L Amado
- Curso de Pós-graduação em Ciências Fisiológicas - Fisiologia Animal Comparada, Universidade Federal do Rio Grande, FURG, Cx. P. 474, CEP 96.201-900, Rio Grande, RS, Brazil
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270
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Shirasaka Y, Suzuki K, Nakanishi T, Tamai I. Differential Effect of Grapefruit Juice on Intestinal Absorption of Statins Due to Inhibition of Organic Anion Transporting Polypeptide and/or P-glycoprotein. J Pharm Sci 2011; 100:3843-53. [DOI: 10.1002/jps.22586] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 04/02/2011] [Accepted: 04/06/2011] [Indexed: 11/06/2022]
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271
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Similar uptake profiles of microcystin-LR and -RR in an in vitro human intestinal model. Toxicology 2011; 290:7-13. [PMID: 21872638 DOI: 10.1016/j.tox.2011.08.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/03/2011] [Accepted: 08/04/2011] [Indexed: 12/20/2022]
Abstract
Microcystins (MCs) are cyclic hepatotoxins produced by various species of cyanobacteria. Their structure includes two variable amino acids (AA) leading to more than 80 MC variants. In this study, we focused on the most common variant, microcystin-LR (MC-LR), and microcystin-RR (MC-RR), a variant differing by only one AA. Despite their structural similarity, MC-LR elicits higher liver toxicity than MC-RR partly due to a discrepancy in their uptake by hepatic organic anion transporters (OATP 1B1 and 1B3). However, even though ingestion is the major pathway of human exposure to MCs, intestinal absorption of MCs has been poorly addressed. Consequently, we investigated the cellular uptake of the two MC variants in the human intestinal cell line Caco-2 by immunolocalization using an anti-MC antibody. Caco-2 cells were treated for 30min to 24h with several concentrations (1-50μM) of both variants. We first confirmed the localization of OATP 3A1 and 4A1 at the cell membrane of Caco-2 cells. Our study also revealed a rapid uptake of both variants in less than 1h. The uptake profiles of the two variants did not differ in our immunostaining study neither with respect to concentration nor the time of exposure. Furthermore, we have demonstrated for the first time the nuclear localization of MC-RR and confirmed that of MC-LR. Finally, our results suggest a facilitated uptake and an active excretion of MC-LR and MC-RR in Caco-2 cells. Further investigation on the role of OATP 3A1 and 4A1 in MC uptake should be useful to clarify the mechanism of intestinal absorption of MCs and contribute in risk assessment of cyanotoxin exposure.
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272
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Pathological modifications following sub-chronic exposure of medaka fish (Oryzias latipes) to microcystin-LR. Reprod Toxicol 2011; 32:329-40. [PMID: 21839164 DOI: 10.1016/j.reprotox.2011.07.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 06/15/2011] [Accepted: 07/25/2011] [Indexed: 12/29/2022]
Abstract
Microcystins (MCs) are toxic monocyclic heptapeptides produced by many cyanobacteria. MCs, especially MC-LR, cause toxic effects in animals and are a recognized potent cause of environmental stress and health hazard in aquatic ecosystems when heavy blooms of cyanobacteria appear. Consequently, one of the major problems is the chronic exposure of fish to cyanotoxins in their natural environment. The present experiment involving chronic exposure confirmed initial findings on acute exposure to MC contamination: exacerbated physiological stress and tissue damage in several tissues of exposed medaka fish. The gonads were affected specifically. In female gonads the modifications included reduction of the vitellus storage, lysis of the gonadosomatic tissue and disruption of the relationships between the follicular cells and the oocytes. In the males, spermatogenesis appeared to be disrupted. This is the first report showing that a cyanotoxin can affect reproductive function, and so can impact on fish reproduction and thus fish stocks.
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273
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Berry JP, Lee E, Walton K, Wilson AE, Bernal-Brooks F. Bioaccumulation of microcystins by fish associated with a persistent cyanobacterial bloom in Lago de Patzcuaro (Michoacan, Mexico). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:1621-1628. [PMID: 21495029 DOI: 10.1002/etc.548] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 08/26/2010] [Accepted: 03/14/2011] [Indexed: 05/30/2023]
Abstract
Lago de Patzcuaro is a historically important freshwater fishery in Mexico. The lake is presently characterized by a persistent bloom of cyanobacteria, specifically dominated by recognized producers of toxic microcystins (MCYSTs). We evaluated MCYSTs in sestonic and dissolved fractions of the water column, as well as representative fish species (silversides, Chirostoma spp.; Goodea sp.; and carp, Cyprinus carpio) obtained from local markets and small commercial catches during the bloom. Samples were evaluated primarily by enzyme-linked immunosorbent assay (ELISA), and secondarily by protein phosphatase (PPase) inhibition assay and liquid chromatography-mass spectrometry (LC-MS). Sestonic MCYST concentration (0.02-0.36 µg/L) generally correlated inversely with distance from the bloom, supporting the bloom as the source of the toxin. Several MCYST variants, including MC-LR, -LA and -LY, as well as didemethyl variants, were identified by LC-MS/MS analysis. All three species of fish bioaccumulated MCYSTs in relevant tissues, and toxin content correlated with trophic level, with highest and lowest levels measured in phytoplanktivorous and zooplanktivorous representatives, respectively. Detection of MCYST in silversides and Goodea sp. is particularly relevant because both are consumed in their entirety, including viscera (e.g., liver) known to primarily accumulate MCYST. These results indicate that Lago de Patzcuaro is indeed characterized by a toxigenic bloom, and that commercially important fish species from the lake accumulate toxic MCYST in tissues relevant to human consumption. As such, this system may represent an ideal model of the trophic transfer of MCYSTs and its relevance to human and environmental health.
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Affiliation(s)
- John P Berry
- Department of Chemistry and Biochemistry, Florida International University, North Miami, Florida, USA.
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274
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Wu Q, Li M, Gao X, Giesy JP, Cui Y, Yang L, Kong Z. Genotoxicity of crude extracts of cyanobacteria from Taihu Lake on carp (Cyprinus carpio). ECOTOXICOLOGY (LONDON, ENGLAND) 2011; 20:1010-1017. [PMID: 21472455 DOI: 10.1007/s10646-011-0670-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/27/2011] [Indexed: 05/30/2023]
Abstract
Genotoxicity of crude cyanobacteria extracts (CBE) from blooms in Taihu Lake, China toward common carp (Cyprinus carpio) was measured. The primary extracellular product was determined by HPLC to be Microcystin-LR (MC-LR, L for leucine and R for arginine) with an average concentration of 2.4 × 10(2) μg MC g(-1) dry weight of cyanobacteria. Acute toxicity to carp, expressed as the 72-h LC(50,) was 53 mg, dw cyanobacteria L(-1). Genotoxicity, as determined by the micronucleus (MN) and comet assays were both dose- and time-depended. Deformities of cellular organelles in liver and gill were observed by use of transmission electron microscopy (TEM). The results showed that MC-LR from cyanobacteria from Taihu Lake could induce genotoxic response and tissue-level morphological changes in common carp.
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Affiliation(s)
- Qin Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Campus, 163 Xianlin Avenue, Nanjing, 210046, People's Republic of China
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275
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Bernard C, Froscio S, Campbell R, Monis P, Humpage A, Fabbro L. Novel toxic effects associated with a tropical Limnothrix/Geitlerinema-like cyanobacterium. ENVIRONMENTAL TOXICOLOGY 2011; 26:260-270. [PMID: 19950362 DOI: 10.1002/tox.20552] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The presence of a toxic strain of a fine filamentous cyanobacterium belonging to the Oscillatorialean family Pseudanabaenacea was detected during a survey of cyanobacterial taxa associated with the presence of cylindrospermopsin in dams in Central Queensland (Australia). The strain, AC0243, was isolated and cultured, its genomic DNA extracted and 16S RNA gene sequenced. Phylogenetic analysis placed AC0243 with Limnothrix species, although this genus appears polyphyletic. Moreover, not all morphological characters are consistent with this genus but more closely fit the description of Geitlerinema unigranulatum (R.N. Singh) Komárek and Azevedo. The potential toxic effects of AC0243 extract were assessed chemically and biologically. Cell free protein synthesis was inhibited by the extract. Exposure of Vero cells to the extract resulted in a significant reduction in cellular ATP levels following 24-72 h incubation. The presence of cylindrospermopsin was excluded based on the nature of responses obtained in cell and cell-free assays; in addition, (i) it could not be detected by HPLC, LC-MS, or immunological assay, and (ii) no genes currently associated with the production of cylindrospermopsin were found in the genome. Other known cyanobacterial toxins were not detected. The apparent novelty of this toxin is discussed.
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Affiliation(s)
- Catherine Bernard
- Centre for Environmental Management, CQ University, Rockhampton, Queensland, Australia
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276
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Gong L, Aranibar N, Han YH, Zhang Y, Lecureux L, Bhaskaran V, Khandelwal P, Klaassen CD, Lehman-McKeeman LD. Characterization of organic anion-transporting polypeptide (Oatp) 1a1 and 1a4 null mice reveals altered transport function and urinary metabolomic profiles. Toxicol Sci 2011; 122:587-97. [PMID: 21561886 DOI: 10.1093/toxsci/kfr114] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Organic anion-transporting polypeptides (Oatp) 1a1 and 1a4 were deleted by homologous recombination, and mice were characterized for Oatp expression in liver and kidney, transport in isolated hepatocytes, in vivo disposition of substrates, and urinary metabolomic profiles. Oatp1a1 and Oatp1a4 proteins were undetected in liver, and both lines were viable and fertile. Hepatic constitutive messenger RNAs (mRNAs) for Oatp1a4, 1b2, or 2b1 were unchanged in Oatp1a1⁻/⁻ mice, whereas renal Oatp1a4 mRNA decreased approximately 50% (both sexes). In Oatp1a4⁻/⁻ mice, no changes in constitutive mRNAs for other Oatps were observed. Uptake of estradiol-17β-D-glucuronide and estrone-3-sulfate in primary hepatocytes decreased 95 and 75%, respectively, in Oatp1a1⁻/⁻ mice and by 60 and 30%, respectively, in Oatp1a4⁻/⁻ mice. Taurocholate uptake decreased by 20 and 50% in Oatp1a1⁻/⁻ and Oatp1a4⁻/⁻ mice, respectively, whereas digoxin was unaffected. Plasma area under the curve (AUC) for estradiol-17β-D-glucuronide increased 35 and 55% in male and female Oatp1a1⁻/⁻ mice, respectively, with a concurrent 50% reduction in liver-to-plasma ratios. In contrast, plasma AUC or tissue concentrations of estradiol-17β-D-glucuronide were unchanged in Oatp1a4⁻/⁻ mice. Plasma AUCs for dibromosulfophthalein increased nearly threefold in male Oatp1a1⁻/⁻ and Oatp1a4⁻/⁻ mice, increased by 40% in female Oatp1a4⁻/⁻ mice, and were unchanged in female Oatp1a1⁻/⁻ mice. In both lines, no changes in serum ALT, bilirubin, and cholesterol were noted. NMR analyses showed no generalized increase in urinary excretion of organic anions. However, urinary excretion of taurine decreased by 30-40% and was accompanied by increased excretion of isethionic acid, a taurine metabolite generated by intestinal bacteria, suggesting some perturbations in intestinal bacteria distribution.
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Affiliation(s)
- Lei Gong
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Co., Princeton, New Jersey 08543, USA
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277
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Malécot M, Marie A, Puiseux-Dao S, Edery M. iTRAQ-based proteomic study of the effects of microcystin-LR on medaka fish liver. Proteomics 2011; 11:2071-8. [DOI: 10.1002/pmic.201000512] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 01/20/2011] [Accepted: 02/17/2011] [Indexed: 11/07/2022]
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278
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Kounnis V, Ioachim E, Svoboda M, Tzakos A, Sainis I, Thalhammer T, Steiner G, Briasoulis E. Expression of organic anion-transporting polypeptides 1B3, 1B1, and 1A2 in human pancreatic cancer reveals a new class of potential therapeutic targets. Onco Targets Ther 2011; 4:27-32. [PMID: 21552413 PMCID: PMC3084305 DOI: 10.2147/ott.s16706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Indexed: 11/23/2022] Open
Abstract
Background: Organic anion-transporting polypeptides (OATPs) are influx transporters that mediate intracellular uptake of selective endogenous and xenobiotic compounds. Identification of new molecular targets and discovery of novel targeted therapies is top priority for pancreatic cancer, which lacks any effective therapy. Materials and methods: We studied expression of OATP 1A2, 1B1, and 1B3 in pancreatic cancer tissue and in cell lines. Formalin-fixed paraffin-embedded biopsy material of 12 human pancreatic cancers was immunohistochemically assessed for protein expression of the three studied influx transporters. Immunohistochemistry was evaluated by experienced pathologists and quantified by use of an automated image analysis system. BxPC-3 and MIA PaCa-2 pancreatic cancer cell lines were used to quantify transcripts of OATP 1B1 and 1B3. Results: OATP 1A2, 1B1, and 1B3 proteins were found ubiquitously expressed in all studied cases. Quantification performed by HistoQuest system revealed that mean intensity was 53 for 1A2, 45 for 1B1, and 167 for OATP 1B1/1B3 on a range scale 0–250 units. At mRNA level, 1B1 and 1B3 were overexpressed in both studied cancer cell lines but not in normal pancreatic tissue. Conclusion: OATPs 1A2, 1B1, and 1B3 are highly expressed in pancreatic adenocarcinoma. We suggest that expression of these transporters in pancreatic cancer justify research efforts towards discovery of novel therapeutics targeting OATPs.
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279
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Feng G, Abdalla M, Li Y, Bai Y. NF-κB mediates the induction of Fas receptor and Fas ligand by microcystin-LR in HepG2 cells. Mol Cell Biochem 2011; 352:209-19. [PMID: 21359529 DOI: 10.1007/s11010-011-0756-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 02/17/2011] [Indexed: 01/27/2023]
Abstract
Microcystin-LR (MC-LR) is the most frequent and most toxic microcystin identified. This natural toxin has multiple features, including inhibitor of protein phosphatases 1 and 2A, inducer of oxidative stress, as well as, tumor initiator and promoter. One unique character of MC-LR is this chemical can accumulate into liver after contacting and lead to severe damage to hepatocytes, such as apoptosis. Fas receptor (Fas) and Fas ligand (FasL) system is a critical signaling system initiating apoptosis. In current study, we explored whether MC-LR could induce Fas and FasL expression in HepG2 cells, a well used in vitro model for the study of human hepatocytes. The data showed MC-LR induced Fas and FasL expression, at both mRNA and protein levels. We also found MC-LR induced apoptosis at the same incubation condition at which it induced Fas and FasL expression. The data also revealed MC-LR promoted nuclear translocation and activation of p65 subunit of NF-κB. By applying siRNA to knock down p65 in HepG2 cells, we successfully impaired the activation of NF-κB by MC-LR. In these p65 knockdown cells, we also observed significant reduction of MC-LR-induced Fas expression, FasL expression, and apoptosis. These findings demonstrate that the NF-κB mediates the induction of Fas and FasL as well as cellular apoptosis by MC-LR in HepG2 cells. The results bring important information for understanding how MC-LR induces apoptosis in hepatocytes.
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Affiliation(s)
- Gong Feng
- Department of Pathology, Northwestern University, Chicago, IL 60613, USA.
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280
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Chen Y, Xu J, Li Y, Han X. Decline of sperm quality and testicular function in male mice during chronic low-dose exposure to microcystin-LR. Reprod Toxicol 2011; 31:551-7. [PMID: 21338672 DOI: 10.1016/j.reprotox.2011.02.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 01/26/2011] [Accepted: 02/13/2011] [Indexed: 10/18/2022]
Abstract
The effects of chronic low-dose exposure to microcystins were preliminarily studied on sperm quality and testicular function in male mice. Microcystin-LR (MC-LR) was orally administered to male mice at 0, 1, 3.2, and 10 μg/L for 3 and 6 months. Our preliminary study found in three-month group, sperm quality declined at 3.2 and 10 μg/L doses, testosterone dropped at 10 μg/L, levels of LH and FSH increased, and Leydig cells exhibited apoptosis. Similar, but more pronounced, effects were observed in groups treated with MC-LR for 6 months. Compared to control (0 μg/L), the rate of sperm abnormality was higher and testosterone levels were lower following administration of 3.2 and 10 μg/L MC-LR and structural damage to the testis was observed with 10 μg/L dose. Thus, chronic low-dose treatment with MC-LR results in substantial toxicity to male reproduction, causing declines in sperm quality, decreased levels of serum testosterone, and injury to the testis.
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Affiliation(s)
- Yu Chen
- Medical School, Nanjing University, Nanjing, Jiangsu 210093, PR China
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281
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Amado LL, Garcia ML, Ramos PB, Yunes JS, Monserrat JM. Influence of a toxic Microcystis aeruginosa strain on glutathione synthesis and glutathione-S-transferase activity in common carp Cyprinus carpio (Teleostei: Cyprinidae). ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2011; 60:319-326. [PMID: 20809345 DOI: 10.1007/s00244-010-9594-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 08/09/2010] [Indexed: 05/29/2023]
Abstract
We evaluated the effects of aqueous extracts of the cyanobacterium-producing microcystin (MC), Microcystis aeruginosa (strain RST9501), on detoxification capacity and glutathione (GSH) synthesis in liver, brain, gill, and muscle-as well as apoptotic protease (calpain) activity in liver and brain-in the common carp Cyprinus carpio (Teleostei: Cyprinidae). Experimental groups were defined as follows: (1) control (CTR); (2) carp treated with an aqueous extract from the toxic cyanobacteria M. aeruginosa in a final MC concentration of 25 μg/kg (MC 25); and (3) carp treated with an aqueous extract from the toxic cyanobacteria M. aeruginosa in a final MC concentration of 50 μg/kg (MC 50). Carp were gavaged with a cyanobacterial aqueous solution or MilliQ water (CTR group). The experiment was conducted for period of 48 h comprising two gavages with a 24-h interval between them. Some of the parameters analyzed in liver, brain, gill, and muscle included activity of the enzymes glutathione-S-transferase (GST), glutamate cysteine ligase (GCL), glutathione reductase (GR), and GSH concentration. We also evaluated GST pi concentration by Western blot as well as calpain activity in liver and brain samples. In carp liver from the MC 50 group, we observed a decrease in GST and GCL activity, which was accompanied by a decreased GSH concentration. In addition, liver calpain activity was highly induced in carp at both MC doses. Thus, MC ingestion affected the liver antioxidant status through decreasing the GSH concentration and the activity of the enzyme involved in its synthesis (GCL). It also decreased the MC detoxification capacity of the liver because total GST activity decreased, a result that cannot be ascribed to GST pi levels. Because GSH acts as an uncompetitive inhibitor of calpain, its decrease should explain the higher activity of this apoptotic enzyme. The main goal of this study was to show that a decrease in GSH concentration is related to decreased activity of GCL, the limiting enzyme involved in GSH synthesis. Because MCs are phosphatase inhibitors and GCL is allosterically inhibited by phosphorylation, the cellular hyperphosphorylation state induced by MC exposure could act as a modulator factor for antioxidant defenses.
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282
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Herfindal L, Myhren L, Kleppe R, Krakstad C, Selheim F, Jokela J, Sivonen K, Døskeland SO. Nostocyclopeptide-M1: a potent, nontoxic inhibitor of the hepatocyte drug transporters OATP1B3 and OATP1B1. Mol Pharm 2011; 8:360-7. [PMID: 21214185 DOI: 10.1021/mp1002224] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have isolated a novel cyanobacterial cyclic peptide (nostocyclopeptide M1; Ncp-M1) that blocks the hepatotoxic action of microcystin (MC) and nodularin (Nod). We show here that Ncp-M1 is nontoxic to primary hepatocytes in long-term culture. Ncp-M1 does not affect any known intracellular targets or pathways involved in MC action, like protein phosphatases, CaM-KII, or ROS-dependent cell death effectors. In support of this conclusion Ncp-M1 had no protective effect when microinjected into cells. Rather, the antitoxin effect was solely due to blocked hepatocyte uptake of MC and Nod. The hepatic uptake of MC and Nod is mainly via the closely related organic anion transporters OATP1B1 and OATP1B3, which also mediate hepatic transport of endogenous metabolites and hormones as well as drugs. OATP1B3 is also expressed in some aggressive cancers, where it confers apoptosis resistance. We show that Ncp-M1 inhibits transport through OATP1B3 and OATP1B1 expressed in HEK293 cells. The Ncp-M1 molecule has several nonproteinogenic amino acids and an imino bond, which hamper its synthesis. Moreover, a cyclic all L-amino acid heptapeptide analogue of Ncp-M1 also inhibits the OATP1B1/1B3 transporters, and with higher OATP1B3 preference than Ncp-M1 itself. The nontoxic Ncp-M1 and its synthetic cyclic peptide analogues thus provide new tools to probe the role of OATB1B1/1B3 mediated drug and metabolite transport in liver and cancer cells. They can also serve as scaffolds to design new, exopeptidase resistant OATP1B3-specific modulators.
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Affiliation(s)
- Lars Herfindal
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
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283
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Niemi M, Pasanen MK, Neuvonen PJ. Organic anion transporting polypeptide 1B1: a genetically polymorphic transporter of major importance for hepatic drug uptake. Pharmacol Rev 2011; 63:157-81. [PMID: 21245207 DOI: 10.1124/pr.110.002857] [Citation(s) in RCA: 463] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The importance of membrane transporters for drug pharmacokinetics has been increasingly recognized during the last decade. Organic anion transporting polypeptide 1B1 (OATP1B1) is a genetically polymorphic influx transporter expressed on the sinusoidal membrane of human hepatocytes, and it mediates the hepatic uptake of many endogenous compounds and xenobiotics. Recent studies have demonstrated that OATP1B1 plays a major, clinically important role in the hepatic uptake of many drugs. A common single-nucleotide variation (coding DNA c.521T>C, protein p.V174A, rs4149056) in the SLCO1B1 gene encoding OATP1B1 decreases the transporting activity of OATP1B1, resulting in markedly increased plasma concentrations of, for example, many statins, particularly of active simvastatin acid. The variant thereby enhances the risk of statin-induced myopathy and decreases the therapeutic indexes of statins. However, the effect of the SLCO1B1 c.521T>C variant is different on different statins. The same variant also markedly affects the pharmacokinetics of several other drugs. Furthermore, certain SLCO1B1 variants associated with an enhanced clearance of methotrexate increase the risk of gastrointestinal toxicity by methotrexate in the treatment of children with acute lymphoblastic leukemia. Certain drugs (e.g., cyclosporine) potently inhibit OATP1B1, causing clinically significant drug interactions. Thus, OATP1B1 plays a major role in the hepatic uptake of drugs, and genetic variants and drug interactions affecting OATP1B1 activity are important determinants of individual drug responses. In this article, we review the current knowledge about the expression, function, substrate characteristics, and pharmacogenetics of OATP1B1 as well as its role in drug interactions, in parts comparing with those of other hepatocyte-expressed organic anion transporting polypeptides, OATP1B3 and OATP2B1.
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Affiliation(s)
- Mikko Niemi
- Department of Clinical Pharmacology, University of Helsinki, PO Box 20, Helsinki, FI-00014, Finland.
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284
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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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285
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Pikula J, Bandouchova H, Hilscherova K, Paskova V, Sedlackova J, Adamovsky O, Knotkova Z, Lany P, Machat J, Marsalek B, Novotny L, Pohanka M, Vitula F. Combined exposure to cyanobacterial biomass, lead and the Newcastle virus enhances avian toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:4984-4992. [PMID: 20701952 DOI: 10.1016/j.scitotenv.2010.07.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Revised: 07/02/2010] [Accepted: 07/15/2010] [Indexed: 05/29/2023]
Abstract
Under environmental conditions, wild birds can be exposed to multiple stressors including natural toxins, anthropogenic pollutants and infectious agents at the same time. This experimental study was successful in testing the hypothesis that adverse effects of cyanotoxins, heavy metals and a non-pathogenic immunological challenge combine to enhance avian toxicity. Mortality occurred in combined exposures to naturally occurring cyanobacterial biomass and lead shots, lead shots and Newcastle vaccination as well as in single lead shot exposure. Mostly acute effects around day 10 were observed. On day 30 of exposure, there were no differences in the liver accumulation of lead in single and combined exposure groups. Interestingly, liver microcystin levels were elevated in birds co-exposed to cyanobacterial biomass together with lead or lead and the Newcastle virus. Significant differences in body weights between all Pb-exposed and Pb-non-exposed birds were found on days 10 and 20. Single exposure to cyanobacterial biomass resulted in hepatic vacuolar dystrophy, whereas co-exposure with lead led to more severe granular dystrophy. Haematological changes were associated with lead exposure, in particular. Biochemical analysis revealed a decrease in glucose and an increase in lactate dehydrogenase in single and combined cyanobacterial and lead exposures, which also showed a decreased antibody response to vaccination. The combined exposure of experimental birds to sub-lethal doses of individual stressors is ecologically realistic. It brings together new pieces of knowledge on avian health. In light of this study, investigators of wild bird die-offs should be circumspect when evaluating findings of low concentrations of contaminants that would not result in mortality on a separate basis. As such it has implications for wildlife biologists, veterinarians and conservationists of avian biodiversity.
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Affiliation(s)
- Jiri Pikula
- University of Veterinary and Pharmaceutical Sciences Brno, Palackeho 1/3, 612 42 Brno, Czech Republic.
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286
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Wang M, Wang D, Lin L, Hong H. Protein profiles in zebrafish (Danio rerio) brains exposed to chronic microcystin-LR. CHEMOSPHERE 2010; 81:716-724. [PMID: 20800265 DOI: 10.1016/j.chemosphere.2010.07.061] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 07/20/2010] [Accepted: 07/28/2010] [Indexed: 05/29/2023]
Abstract
Microcystin-LR (MCLR) is a commonly encountered blue-green algal hepatotoxin and a known inhibitor of cellular protein phosphatase (PP), however, little is known about its neurotoxicity. This study investigated the protein profiles of zebrafish (Danio rerio) brains chronically exposed to MCLR concentrations (2 or 20 μg L(-1)) using the proteomic approach. The results showed that MCLR strikingly enhanced toxin accumulation and the PP activity in zebrafish brains after 30 d exposure. Comparison of two-dimensional electrophoresis protein profiles of MCLR exposed and non-exposed zebrafish brains revealed that the abundance of 30 protein spots was remarkably altered in response to MCLR exposure. These proteins are involved in cytoskeleton assembly, macromolecule metabolism, oxidative stress, signal transduction, and other functions (e.g. transporting, protein degradation, apoptosis and translation), indicating that MCLR toxicity in the fish brain is complex and diverse. The chronic neurotoxicity of MCLR might initiate the PP pathway via an upregulation of PP2C in the zebrafish brain, in addition to the reactive oxygen species pathway. Additionally, the increase of vitellogenin abundance in MCLR exposed zebrafish brains suggested that MCLR might mimic the effects of endocrine disrupting chemicals. This study demonstrated that MCLR causes neurotoxicity in zebrafish at the proteomic level, which provides a new insight into MCLR toxicity in aquatic organisms and human beings.
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Affiliation(s)
- Minghua Wang
- State Key Laboratory of Marine Environmental Science/Environmental Science Research Center, Xiamen University, Xiamen 361005, People's Republic of China
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287
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Feurstein D, Kleinteich J, Heussner AH, Stemmer K, Dietrich DR. Investigation of microcystin congener-dependent uptake into primary murine neurons. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:1370-5. [PMID: 20472527 PMCID: PMC2957914 DOI: 10.1289/ehp.0901289] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 05/15/2010] [Indexed: 05/16/2023]
Abstract
BACKGROUND Contamination of natural waters by toxic cyanobacteria is a growing problem worldwide, resulting in serious water pollution and human health hazards. Microcystins (MCs) represent a group of > 80 cyclic heptapeptides, mediating cytotoxicity via specific protein phosphatase (PP) inhibition at equimolar concentrations (comparable toxicodynamics). Because of the structure and size of MCs, active uptake into cells occurs via organic anion-transporting polypeptides (OATP/Oatp), as confirmed for liver-specific human OATP1B1 and OATP1B3, mouse Oatp1b2 (mOatp1b2), skate Oatp1d1, and the more widely distributed OATP1A2 expressed, for example, at the blood-brain barrier. Tissue-specific and cell-type-specific expression of OATP/Oatp transporters and specific transport of MC congeners (toxicokinetics) therefore appear prerequisite for the reported toxic effects in humans and other species upon MC exposure. Beyond hepatotoxicity induced by the MC-LR congener, the effects of other MC congeners, especially neuronal uptake and toxicity, are unknown. OBJECTIVES In this study we examined the expression of mOatps and the uptake of congeners MC-LR, MC-LW, and MC-LF in primary murine neurons. METHODS Intracellular MC accumulation was indicated indirectly via uptake inhibition experiments and directly confirmed by Western blot analysis and a PP inhibition assay. Neuronal mOatp expression was verified at the mRNA and protein level. RESULTS MCs can cross neuronal cell membranes, with a subsequent decrease of PP activity. Of 15 mOatps, 12 were expressed at the mRNA level, but we found detectable protein levels for only two: mOatp1a5 (Slco1a5) and the known MC-LR transporter mOatp1b2 (Slco1b2). CONCLUSIONS These data suggest mOatp-mediated uptake of MC congeners into neurons, thus corroborating earlier assumptions of the neurotoxic potential of MCs.
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Affiliation(s)
- Daniel Feurstein
- Human and Environmental Toxicology, University of Konstanz, Konstanz, Germany.
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288
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Takumi S, Komatsu M, Furukawa T, Ikeda R, Sumizawa T, Akenaga H, Maeda Y, Aoyama K, Arizono K, Ando S, Takeuchi T. p53 Plays an important role in cell fate determination after exposure to microcystin-LR. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:1292-8. [PMID: 20421190 PMCID: PMC2944092 DOI: 10.1289/ehp.1001899] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 04/26/2010] [Indexed: 05/03/2023]
Abstract
BACKGROUND Microcystin-LR, a cyclic heptapeptide, possesses the ability to inhibit the serine/threonine protein phosphatases PP1 and PP2A and, consequently, exhibits acute hepatocytotoxicity. Moreover, microcystin-LR induces cellular proliferation, resulting in tumor-promoting activity in hepatocytes. However, mechanisms that regulate the balance between cell death and proliferation after microcystin-LR treatment remain unclear. OBJECTIVE We examined the contribution of the transcription factor p53, as well as that of the hepatic uptake transporter for microcystin-LR, organic anion transporting polypeptide 1B3 (OATP1B3), to the cellular response to microcystin-LR exposure. METHODS We analyzed intracellular signaling responses to microcystin-LR by immunoblotting and real-time reverse-transcriptase polymerase chain reaction techniques using HEK293 human embryonic kidney cells stably transfected with SLCO1B3 (HEK293-OATP1B3). In addition, we analyzed the effect of attenuation of p53 function, via the p53 inhibitor pifithrin-alpha, and knockdown of p53 mRNA on the cytotoxicity of microcystin-LR using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS Microcystin-LR induced the phosphorylation and accumulation of p53 in HEK293-OATP1B3 cells, which resulted in up-regulation of the expression of p53 transcript targets, including p21 and seven in absentia homolog 1 (siah-1). In addition, microcystin-LR activated Akt signaling through the phosphorylation of Akt and glycogen synthase kinase 3beta. Although Akt signaling was activated, the accumulation of p53 led cells to apoptosis after treatment with 50 nM microcystin-LR for 24 hr. Both pharmacological inhibition of transcription factor activity of p53 by pifithrin-alpha and knockdown of p53 with small hairpin RNA attenuated the susceptibility of HEK293-OATP1B3 cells to microcystin-LR. CONCLUSIONS This study demonstrates the importance of p53 in the regulation of cell fate after exposure to microcystin-LR. Our results suggest that, under conditions of p53 inactivation (including p53 mutation), chronic exposure to low doses of microcystin-LR may lead to cell proliferation through activation of Akt signaling. Results of this study may contribute to the development of chemoprevention and chemotherapeutic approaches to microcystin-LR poisoning.
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Affiliation(s)
- Shota Takumi
- Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
- Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, Japan
| | - Masaharu Komatsu
- Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
- Department of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
- Address correspondence to M. Komatsu, Department of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, 890-0056 Kagoshima, Japan. Telephone: 81-99-286-4200. Fax: 81-99-286-4200. E-mail:
| | | | - Ryuji Ikeda
- Department of Clinical Pharmacy and Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tomoyuki Sumizawa
- Department of Environmental Toxicology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Hitomi Akenaga
- Department of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
| | - Yuta Maeda
- Department of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
| | - Kohji Aoyama
- Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Koji Arizono
- Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, Japan
| | - Seiichi Ando
- Department of Food and Chemical Biology, Faculty of Fisheries, Kagoshima University, Kagoshima, Japan
| | - Toru Takeuchi
- Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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289
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Dias E, Matos P, Pereira P, Batoréu M, Silva M, Jordan P. Microcystin-LR activates the ERK1/2 kinases and stimulates the proliferation of the monkey kidney-derived cell line Vero-E6. Toxicol In Vitro 2010; 24:1689-95. [DOI: 10.1016/j.tiv.2010.05.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 05/20/2010] [Accepted: 05/21/2010] [Indexed: 12/31/2022]
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290
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Oftedal L, Skjærven KH, Coyne RT, Edvardsen B, Rohrlack T, Skulberg OM, Døskeland SO, Herfindal L. The apoptosis-inducing activity towards leukemia and lymphoma cells in a cyanobacterial culture collection is not associated with mouse bioassay toxicity. J Ind Microbiol Biotechnol 2010; 38:489-501. [PMID: 20689978 PMCID: PMC3062024 DOI: 10.1007/s10295-010-0791-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 07/21/2010] [Indexed: 11/29/2022]
Abstract
Cyanobacteria (83 strains and seven natural populations) were screened for content of apoptosis (cell death)-inducing activity towards neoplastic cells of the immune (jurkat acute T-cell lymphoma) and hematopoetic (acute myelogenic leukemia) lineage. Apoptogenic activity was frequent, even in strains cultured for decades, and was unrelated to whether the cyanobacteria had been collected from polar, temperate, or tropic environments. The activity was more abundant in the genera Anabaena and Microcystis compared to Nostoc, Phormidium, Planktothrix, and Pseudanabaena. Whereas the T-cell lymphoma apoptogens were frequent in organic extracts, the cell death-inducing activity towards leukemia cells resided mainly in aqueous extracts. The cyanobacteria were from a culture collection established for public health purposes to detect toxic cyanobacterial blooms, and 54 of them were tested for toxicity by the mouse bioassay. We found no correlation between the apoptogenic activity in the cyanobacterial isolates with their content of microcystin, nor with their ability to elicit a positive standard mouse bioassay. Several strains produced more than one apoptogen, differing in biophysical or biological activity. In fact, two strains contained microcystin in addition to one apoptogen specific for the AML cells, and one apoptogen specific for the T-cell lymphoma. This study shows the potential of cyanobacterial culture collections as libraries for bioactive compounds, since strains kept in cultures for decades produced apoptogens unrelated to the mouse bioassay detectable bloom-associated toxins.
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Affiliation(s)
- Linn Oftedal
- Department of Biomedicine, University of Bergen, Jonas Lies Vei 91, 5009 Bergen, Norway
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291
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Lance E, Josso C, Dietrich D, Ernst B, Paty C, Senger F, Bormans M, Gérard C. Histopathology and microcystin distribution in Lymnaea stagnalis (Gastropoda) following toxic cyanobacterial or dissolved microcystin-LR exposure. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 98:211-220. [PMID: 20227118 DOI: 10.1016/j.aquatox.2010.02.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 02/11/2010] [Accepted: 02/15/2010] [Indexed: 05/28/2023]
Abstract
The accumulation of hepatotoxic microcystins (MCs) in gastropods has been demonstrated to be higher following grazing of toxic cyanobacteria than from MCs dissolved in ambient water. Previous studies, however, did not adequately consider MCs covalently bound to protein phosphatases, which may represent a considerably part of the MC body burden. Thus, using an immunohistochemical method, we examined and compared the histopathology and organ distribution of covalently bound MCs in Lymnaea stagnalis following a 5-week exposure to (i) dmMC-LR, dmMC-RR, and MC-YR-producing Planktothrix agardhii (5 microg MC-LReqL(-1)) and (ii) dissolved MC-LR (33 and 100 microgL(-1)). A subsequent 3-week depuration investigated potential MC elimination and tissue regeneration. Following both exposures, bound MCs were primarily observed in the digestive gland and tract of L. stagnalis. Snails exposed to toxic cyanobacteria showed severe and widespread necrotic changes in the digestive gland co-occurring with a pronounced cytoplasmic presence of MCs in digestive cells and in the lumen of digestive lobules. Snails exposed to dissolved MC-LR showed moderate and negligible pathological changes of the digestive gland co-occurring with a restrained presence of MCs in the apical membrane of digestive cells and in the lumen of digestive lobules. These results confirm lower uptake of dissolved MC-LR and correspondingly lower cytotoxicity in the digestive gland of L. stagnalis. In contrast, after ingestion of MC-containing cyanobacterial filaments, the most likely longer residual time within the digestive gland and/or the MC variant involved (e.g., MC-YR) allowed for increased MC uptake, consequently a higher MC burden in situ and thus a more pronounced ensuing pathology. While no pathological changes were observed in kidney, foot and the genital gland, MCs were detected in spermatozoids and oocytes of all exposed snails, most likely involving a hemolymph transport from the digestive system to the genital gland. The latter results indicate the potential for adverse impact of MCs on gastropod health and reproduction as well as the possible transfer of MCs to higher trophic levels of the food web.
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Affiliation(s)
- Emilie Lance
- UMR CNRS 6553 ECOBIO, Université de Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes, France.
| | - Celine Josso
- UMR INRA Bio3P, Université de Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France
| | - Daniel Dietrich
- Human & Environmental Toxicology Group, University of Konstanz, D-78457 Konstanz, Germany
| | - Bernhard Ernst
- Human & Environmental Toxicology Group, University of Konstanz, D-78457 Konstanz, Germany
| | - Chrystelle Paty
- UMR INRA Bio3P, Université de Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France
| | - Fabrice Senger
- UMR CNRS 6026, Université de Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex, France
| | - Myriam Bormans
- UMR CNRS 6553 ECOBIO, Université de Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes, France
| | - Claudia Gérard
- UMR CNRS 6553 ECOBIO, Université de Rennes 1, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes, France
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292
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Zhang H, Song YN, Liu WG, Guo XL, Yu LG. Regulation and role of organic anion-transporting polypeptides (OATPs) in drug delivery at the choroid plexus. J Clin Neurosci 2010; 17:679-84. [DOI: 10.1016/j.jocn.2009.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 09/28/2009] [Accepted: 11/10/2009] [Indexed: 11/25/2022]
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293
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Cyanobacterial extracts and microcystin-LR are inactive in the micronucleus assay in vivo and in vitro. Mutat Res 2010; 699:5-10. [PMID: 20381641 DOI: 10.1016/j.mrgentox.2010.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 01/22/2010] [Accepted: 01/29/2010] [Indexed: 11/24/2022]
Abstract
Cyanobacteria are sometimes widespread in lakes and can produce potent toxins, which can be dangerous for animals that drink the water, e.g. cattle and dogs. If the toxins are taken up by fish and other organisms in the food chain, or occur in drinking-water, they may pose a problem also for humans. Microcystin-LR, a hepatotoxic cyclic peptide, is one of the most frequently found cyanobacterial toxins. Data on the genotoxic potential of microcystin-LR and other cyanobacterial toxins are contradictory. Here we report results of the micronucleus assay carried out in vivo and in vitro with these toxins. To increase the sensitivity, we used the flow cytometry-based micronucleus assay in the mouse. In this study both pure microcystin-LR and cyanobacterial extracts originating from four different lakes in Sweden were analysed. Although doses up to near lethality were used and an average of 200,000 young erythrocytes, polychromatic erythrocytes, were analysed from each animal, no genotoxic effect was observed, nor could any effect be shown in the in vitro micronucleus study, using human lymphocytes. These results show that the low concentration of microcystins that now and then occur in drinking-water does not increase the cancer risk through chromosome breaks or mal-distribution of chromosomes.
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294
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Jasionek G, Zhdanov A, Davenport J, Bláha L, Papkovsky DB. Mitochondrial toxicity of microcystin-LR on cultured cells: application to the analysis of contaminated water samples. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:2535-2541. [PMID: 20192251 DOI: 10.1021/es903157h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Microcystins (MC) are potent hepatic toxins delivered into the cells by organic anion transporting peptides (OATP) where they target protein phosphatases and mitochondria. We analyzed the effects of MC-LR on primary hepatocytes, HepG2, and Jurkat T cells, and isolated rat liver mitochondria by measuring changes in O(2) consumption by optical oxygen sensing technique. Respiration of fresh primary hepatocytes was inhibited by MC-LR with EC50 = 2.74 +/- 0.65 nM, whereas an uncoupling effect on mitochondrial state 2 and state 3 respiration was observed with glutamate/malate as a substrate. HepG2 and Jurkat T cells lacking OATP showed no sensitivity to MC-LR; however, facilitated delivery of MC-LR resulted in a marked enhancement of HepG2 O(2) consumption and inhibition of Jurkat O(2) consumption at >or=0.1 nM. The respiratory response did not coincide with changes in viability, total cellular ATP, extracellular acidification, ROS formation, or protein phosphorylation, which were detectable at higher MC-LR doses. Such prominent effect on cellular respiration was therefore used for the detection of MC-LR in environmental samples. A simple and sensitive screening assay for MC-LR toxicity was developed, which uses Jurkat cells, facilitated delivery of the toxin(s) and measurement on a fluorescent reader. The assay was applied to a panel of environmental samples suspected to contain MC and benchmarked against the ELISA test. It allowed identification of toxic samples and quantification of both nonspecific and MC-LR type of toxicity.
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Affiliation(s)
- Grzegorz Jasionek
- Biochemistry Department, University College Cork, College Road, Cork, Ireland
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295
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El Ghazali I, Saqrane S, Carvalho AP, Ouahid Y, Del Campo FF, Vasconcelos V, Oudra B. Effects of the microcystin profile of a cyanobacterial bloom on growth and toxin accumulation in common carp Cyprinus carpio larvae. JOURNAL OF FISH BIOLOGY 2010; 76:1415-1430. [PMID: 20537022 DOI: 10.1111/j.1095-8649.2010.02572.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A 12 day growth trial was conducted to compare the effect of the variation in microcystins (MC) composition of two bloom samples of Microcystis aeruginosa on the growth performance and microcystin accumulation in common carp Cyprinus carpio larvae. Two M. aeruginosa natural bloom samples with different MC profiles were collected and larvae were exposed to cyanobacterial cells through their diet. Three diets, a basal control diet and two diets prepared from the basal diet plus the same toxins content (60 ng MC g(-1) diet) of each cyanobacterial bloom, were given at the same ration level to three groups of larvae during the experimental period. Larval mass and standard length from day 9 were significantly different between cyanobacterial treatments and in both cases lower than that of the control. The MC accumulation by larvae, inversely correlated with the growth performance, was also significantly different between cyanobacterial treatments (26.96 v. 17.32 ng g(-1) at the end of the experimental period). These results indicate that MC variants profile may have effects on the toxin uptake and toxicity. To date, this is the first laboratory study to show that fish accumulate MC depending on the toxin profile of the cyanobacterial bloom.
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Affiliation(s)
- I El Ghazali
- Department of Biology, Laboratory of Biology and Biotechnology of Microorganisms, Microbiology and Environmental Toxicology Unit, Faculty of Sciences Semlalia Marrakech, University Cadi Ayyad, P.O. Box 2390, Marrakech 40000, Morocco
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296
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Sainis I, Fokas D, Vareli K, Tzakos AG, Kounnis V, Briasoulis E. Cyanobacterial cyclopeptides as lead compounds to novel targeted cancer drugs. Mar Drugs 2010; 8:629-57. [PMID: 20411119 PMCID: PMC2857373 DOI: 10.3390/md8030629] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 02/10/2010] [Accepted: 02/26/2010] [Indexed: 12/22/2022] Open
Abstract
Cyanobacterial cyclopeptides, including microcystins and nodularins, are considered a health hazard to humans due to the possible toxic effects of high consumption. From a pharmacological standpoint, microcystins are stable hydrophilic cyclic heptapeptides with a potential to cause cellular damage following uptake via organic anion-transporting polypeptides (OATP). Their intracellular biological effects involve inhibition of catalytic subunits of protein phosphatase 1 (PP1) and PP2, glutathione depletion and generation of reactive oxygen species (ROS). Interestingly, certain OATPs are prominently expressed in cancers as compared to normal tissues, qualifying MC as potential candidates for cancer drug development. In the era of targeted cancer therapy, cyanotoxins comprise a rich source of natural cytotoxic compounds with a potential to target cancers expressing specific uptake transporters. Moreover, their structure offers opportunities for combinatorial engineering to enhance the therapeutic index and resolve organ-specific toxicity issues. In this article, we revisit cyanobacterial cyclopeptides as potential novel targets for anticancer drugs by summarizing existing biomedical evidence, presenting structure-activity data and discussing developmental perspectives.
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Affiliation(s)
- Ioannis Sainis
- Human Cancer Biobank Center, University of Ioannina, Greece; E-Mails:
(I.S.);
(K.V.);
(A.T.)
| | - Demosthenes Fokas
- Department of Materials Science and Engineering, University of Ioannina, Greece; E-Mail:
(D.F.)
| | - Katerina Vareli
- Human Cancer Biobank Center, University of Ioannina, Greece; E-Mails:
(I.S.);
(K.V.);
(A.T.)
- Department of Biological Applications and Technologies, University of Ioannina, Greece
| | - Andreas G. Tzakos
- Human Cancer Biobank Center, University of Ioannina, Greece; E-Mails:
(I.S.);
(K.V.);
(A.T.)
- Department of Chemistry, University of Ioannina, Greece
| | | | - Evangelos Briasoulis
- Human Cancer Biobank Center, University of Ioannina, Greece; E-Mails:
(I.S.);
(K.V.);
(A.T.)
- School of Medicine, University of Ioannina, Greece; E-Mail:
(V.K.)
- * Author to whom correspondence should be addressed; E-Mail:
or
; Tel.: +30-265-100-7713; Fax: +30-265-100-8087
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297
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Stewart I. Environmental risk factors for temporal lobe epilepsy – Is prenatal exposure to the marine algal neurotoxin domoic acid a potentially preventable cause? Med Hypotheses 2010; 74:466-81. [DOI: 10.1016/j.mehy.2009.10.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Accepted: 10/04/2009] [Indexed: 01/29/2023]
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298
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Meyer zu Schwabedissen HE, Kim RB. Hepatic OATP1B transporters and nuclear receptors PXR and CAR: interplay, regulation of drug disposition genes, and single nucleotide polymorphisms. Mol Pharm 2010; 6:1644-61. [PMID: 19558188 DOI: 10.1021/mp9000298] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Drug uptake transporters are now increasingly recognized as clinically relevant determinants of variable drug responsiveness and unexpected drug-drug interactions. Emerging evidence strongly suggests members of the organic anion transporting polypeptide (OATP) family appear to be particularly important to the disposition of many drugs in clinical use today. Specifically, the liver-enriched OATP1B subfamily members OATP1B1 and OATP1B3 exhibit broad substrate specificity and the ability to transport drugs which are ligands for xenobiotic sensing nuclear receptors such as the pregnane X receptor (PXR) and the constitutive androstane receptor (CAR). Accordingly, OATP1B transporters may indirectly regulate expression of drug metabolism genes via modulation of the intracellular concentration of PXR and CAR ligands. Moreover, a number of functionally important single nucleotide polymorphisms (SNPs) in OATP1B transporters have been described. In this review, a brief summary of known SNPs in PXR and CAR will be followed by an in-depth outline of OATP1B1 and OATP1B3 transporters particularly in relation to the known SNPs in these OATPs and the interplay between OATP1B transporters with PXR and CAR, both in vitro and in vivo.
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Hao L, Xie P, Li H, Li G, Xiong Q, Wang Q, Qiu T, Liu Y. Transcriptional alteration of cytoskeletal genes induced by microcystins in three organs of rats. Toxicon 2010; 55:1378-86. [PMID: 20184910 DOI: 10.1016/j.toxicon.2010.02.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/07/2010] [Accepted: 02/16/2010] [Indexed: 10/19/2022]
Abstract
This study explored the mechanisms of toxicity of microcystins by measuring the transcription levels of nine cytoskeletal genes (actin, tubulin, vimentin, ezrin, radixin, moesin, MAP1b, tau, stathmin) in the liver, kidney and spleen of male Wistar rats treated with microcystins at a dose of 80 microg MC-LReq kg(-1) bw. Microcystins disrupted the transcriptional homeostasis of cytoskeletal genes in these organs. Changes in the transcription of four genes (beta-actin, ezrin, radixin and tau) in liver, one gene (stathmin) in kidney, and one gene (radixin) in spleen were significantly correlated with the tissue concentration of microcystins. However, the influences on the transcription of most genes we studied were greater in the liver than in the kidney or spleen. The effects of microcystins on the transcription of cytoskeletal genes may explain some of the morphological and pathological changes observed in these organs and provide new information on the hepatotoxicity of these compounds. Additionally, transcriptional changes in tumor-associated cytoskeletal genes (ezrin, moesin and stathmin) that were observed in the present study provide a possible clue to the tumor-promoting potential of microcystins and their influences on the transcription of MAP1b and tau imply possible neurological toxicity of microcystins in vertebrates.
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Affiliation(s)
- Le Hao
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory for Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, The Chinese Academy of Sciences, Donghu South Road 7, Wuhan 430072, People's Republic of China
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Amado LL, Monserrat JM. Oxidative stress generation by microcystins in aquatic animals: why and how. ENVIRONMENT INTERNATIONAL 2010; 36:226-235. [PMID: 19962762 DOI: 10.1016/j.envint.2009.10.010] [Citation(s) in RCA: 203] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 09/09/2009] [Accepted: 10/27/2009] [Indexed: 05/28/2023]
Abstract
Microcystins (MICs) are potent toxins produced worldwide by cyanobacteria during bloom events. Phosphatases inhibition is a well recognized effect of this kind of toxins as well as oxidative stress. However, it is not fully understood why and how MICs exposure can lead to an excessive formation of reactive oxygen species (ROS) that culminate in oxidative damage. Some evidences suggest a close connection between cellular hyperphosphorylation state and oxidative stress generation induced by MICs exposure. It is shown, based on literature data, that MICs incorporation per se can be the first event that triggers glutathione depletion and the consequent increase in ROS concentration. Also, literature data suggest that hyperphosphorylated cellular environment induced by MICs exposure can modulate antioxidant enzymes, contributing to the generation of oxidative damage. This review summarizes information on MICs toxicity in aquatic animals, focusing on mechanistic aspects, and rise questions that in our opinion needs to be further investigated.
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Affiliation(s)
- L L Amado
- Curso de Pós-graduação em Ciências Fisiológicas - Fisiologia Animal Comparada, Cx. P. 474, CEP 96.201-900, Rio Grande, RS, Brazil
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