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Ge K, Du X, Liu H, Meng R, Wu C, Zhang Z, Liang X, Yang J, Zhang H. The cytotoxicity of microcystin-LR: ultrastructural and functional damage of cells. Arch Toxicol 2024; 98:663-687. [PMID: 38252150 DOI: 10.1007/s00204-023-03676-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024]
Abstract
Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria, which is widely distributed in eutrophic water bodies and has multi-organ toxicity. Previous cytotoxicity studies have mostly elucidated the effects of MC-LR on intracellular-related factors, proteins, and DNA at the molecular level. However, there have been few studies on the adverse effects of MC-LR on cell ultrastructure and function. Therefore, research on the cytotoxicity of MC-LR in recent years was collected and summarized. It was found that MC-LR can induce a series of cytotoxic effects, including decreased cell viability, induced autophagy, apoptosis and necrosis, altered cell cycle, altered cell morphology, abnormal cell migration and invasion as well as leading to genetic damage. The above cytotoxic effects were related to the damage of various ultrastructure and functions such as cell membranes and mitochondria. Furthermore, MC-LR can disrupt cell ultrastructure and function by inducing oxidative stress and inhibiting protein phosphatase activity. In addition, the combined toxic effects of MC-LR and other environmental pollutants were investigated. This review explored the toxic targets of MC-LR at the subcellular level, which will provide new ideas for the prevention and treatment of multi-organ toxicity caused by MC-LR.
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Affiliation(s)
- Kangfeng Ge
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Xingde Du
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Haohao Liu
- Department of Public Health, First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450001, China
| | - Ruiyang Meng
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Chunrui Wu
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Zongxin Zhang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Xiao Liang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Jun Yang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China
| | - Huizhen Zhang
- College of Public Health, Zhengzhou University, Zhengzhou, 450001, China.
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Chowdhury RR, Rose S, Ezan F, Sovadinová I, Babica P, Langouët S. Hepatotoxicity of cyanotoxin microcystin-LR in human: Insights into mechanisms of action in the 3D culture model Hepoid-HepaRG. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 342:123047. [PMID: 38036087 DOI: 10.1016/j.envpol.2023.123047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 11/03/2023] [Accepted: 11/23/2023] [Indexed: 12/02/2023]
Abstract
Microcystin-LR (MC-LR) is a potent hepatotoxin produced by harmful cyanobacterial blooms (CyanoHABs). MC-LR targets highly differentiated hepatocytes expressing organic anion transporting polypeptides OATP1B1 and OATP1B3 that are responsible for hepatocellular uptake of the toxin. The present study utilized an advanced 3D in vitro human liver model Hepoid-HepaRG based on the cultivation of collagen-matrix embedded multicellular spheroids composed of highly differentiated and polarized hepatocyte-like cells. 14-d-old Hepoid-HepaRG cultures showed increased expression of OATP1B1/1B3 and sensitivity to MC-LR cytotoxicity at concentrations >10 nM (48 h exposure, EC20 = 26 nM). MC-LR induced neither caspase 3/7 activity nor expression of the endoplasmic reticulum stress marker gene BiP/GRP78, but increased release of pro-inflammatory cytokine IL-8, indicating a necrotic type of cell death. Subcytotoxic (10 nM) and cytotoxic (≥100 nM) MC-LR concentrations disrupted hepatocyte functions, such as xenobiotic metabolism phase-I enzyme activities (cytochrome P450 1A/1B) and albumin secretion, along with reduced expression of CYP1A2 and ALB genes. MC-LR also decreased expression of HNF4A gene, a critical regulator of hepatocyte differentiation and function. Genes encoding hepatobiliary membrane transporters (OATP1B1, BSEP, NTCP), hepatocyte gap junctional gene connexin 32 and the epithelial cell marker E-cadherin were also downregulated. Simultaneous upregulation of connexin 43 gene, primarily expressed by liver progenitor and non-parenchymal cells, indicated a disruption of tissue homeostasis. This was associated with a shift in the expression ratio of E-cadherin to N-cadherin towards the mesenchymal cell marker, a process linked to epithelial-mesenchymal transition (EMT) and hepatocarcinogenesis. The effects observed in the human liver cell in vitro model revealed mechanisms that can potentially contribute to the MC-LR-induced promotion and progression of hepatocellular carcinoma (HCC). Hepoid-HepaRG cultures provide a robust, accessible and versatile in vitro model, capable of sensitively detecting hepatotoxic effects at toxicologically relevant concentrations, allowing for assessing hepatotoxicity mechanisms, human health hazards and impacts of environmental hepatotoxins, such as MC-LR.
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Affiliation(s)
- Riju R Chowdhury
- Masaryk University, Faculty of Science, RECETOX, Kotlářská 2, 61137, Brno, Czech Republic
| | - Sophie Rose
- University of Rennes, Inserm, EHESP, Irset (Institut de Recherche en santé, environnement et travail), UMR_S 1085, 35000, Rennes, France
| | - Frédéric Ezan
- University of Rennes, Inserm, EHESP, Irset (Institut de Recherche en santé, environnement et travail), UMR_S 1085, 35000, Rennes, France
| | - Iva Sovadinová
- Masaryk University, Faculty of Science, RECETOX, Kotlářská 2, 61137, Brno, Czech Republic
| | - Pavel Babica
- Masaryk University, Faculty of Science, RECETOX, Kotlářská 2, 61137, Brno, Czech Republic
| | - Sophie Langouët
- University of Rennes, Inserm, EHESP, Irset (Institut de Recherche en santé, environnement et travail), UMR_S 1085, 35000, Rennes, France.
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Svirčev Z, Chen L, Sántha K, Drobac Backović D, Šušak S, Vulin A, Palanački Malešević T, Codd GA, Meriluoto J. A review and assessment of cyanobacterial toxins as cardiovascular health hazards. Arch Toxicol 2022; 96:2829-2863. [PMID: 35997789 PMCID: PMC9395816 DOI: 10.1007/s00204-022-03354-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 08/02/2022] [Indexed: 12/14/2022]
Abstract
Eutrophicated waters frequently support bloom-forming cyanobacteria, many of which produce potent cyanobacterial toxins (cyanotoxins). Cyanotoxins can cause adverse health effects in a wide range of organisms where the toxins may target the liver, other internal organs, mucous surfaces and the skin and nervous system. This review surveyed more than 100 studies concerning the cardiovascular toxicity of cyanotoxins and related topics. Over 60 studies have described various negative effects on the cardiovascular system by seven major types of cyanotoxins, i.e. the microcystin (MC), nodularin (NOD), cylindrospermopsin (CYN), anatoxin (ATX), guanitoxin (GNTX), saxitoxin (STX) and lyngbyatoxin (LTX) groups. Much of the research was done on rodents and fish using high, acutely toxin concentrations and unnatural exposure routes (such as intraperitoneal injection), and it is thus concluded that the emphasis in future studies should be on oral, chronic exposure of mammalian species at environmentally relevant concentrations. It is also suggested that future in vivo studies are conducted in parallel with studies on cells and tissues. In the light of the presented evidence, it is likely that cyanotoxins do not constitute a major risk to cardiovascular health under ordinary conditions met in everyday life. The risk of illnesses in other organs, in particular the liver, is higher under the same exposure conditions. However, adverse cardiovascular effects can be expected due to indirect effects arising from damage in other organs. In addition to risks related to extraordinary concentrations of the cyanotoxins and atypical exposure routes, chronic exposure together with co-existing diseases could make some of the cyanotoxins more dangerous to cardiovascular health.
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Affiliation(s)
- Zorica Svirčev
- University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, UNS, Trg Dositeja Obradovića 2, 21000, Novi Sad, Serbia.
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Tykistökatu 6A, 20520, Turku, Finland.
| | - Liang Chen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming, 650500, China
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology (IHB), Chinese Academy of Sciences (CAS), Wuhan, 430072, China
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Faculty of Water Resources and Hydroelectric Engineering, Xi'an University of Technology, Xi'an, 710048, China
| | - Kinga Sántha
- University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, UNS, Trg Dositeja Obradovića 2, 21000, Novi Sad, Serbia
| | - Damjana Drobac Backović
- University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, UNS, Trg Dositeja Obradovića 2, 21000, Novi Sad, Serbia
| | - Stamenko Šušak
- University of Novi Sad, Faculty of Medicine, UNS, Hajduk Veljkova 3, 21000, Novi Sad, Serbia
- Institute of Cardiovascular Diseases of Vojvodina, Sremska Kamenica, Serbia
| | - Aleksandra Vulin
- University of Novi Sad, Faculty of Medicine, UNS, Hajduk Veljkova 3, 21000, Novi Sad, Serbia
- Institute of Cardiovascular Diseases of Vojvodina, Sremska Kamenica, Serbia
| | - Tamara Palanački Malešević
- University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, UNS, Trg Dositeja Obradovića 2, 21000, Novi Sad, Serbia
| | - Geoffrey A Codd
- School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Jussi Meriluoto
- University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, UNS, Trg Dositeja Obradovića 2, 21000, Novi Sad, Serbia
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Tykistökatu 6A, 20520, Turku, Finland
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Lad A, Breidenbach JD, Su RC, Murray J, Kuang R, Mascarenhas A, Najjar J, Patel S, Hegde P, Youssef M, Breuler J, Kleinhenz AL, Ault AP, Westrick JA, Modyanov NN, Kennedy DJ, Haller ST. As We Drink and Breathe: Adverse Health Effects of Microcystins and Other Harmful Algal Bloom Toxins in the Liver, Gut, Lungs and Beyond. Life (Basel) 2022; 12:life12030418. [PMID: 35330169 PMCID: PMC8950847 DOI: 10.3390/life12030418] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 12/19/2022] Open
Abstract
Freshwater harmful algal blooms (HABs) are increasing in number and severity worldwide. These HABs are chiefly composed of one or more species of cyanobacteria, also known as blue-green algae, such as Microcystis and Anabaena. Numerous HAB cyanobacterial species produce toxins (e.g., microcystin and anatoxin—collectively referred to as HAB toxins) that disrupt ecosystems, impact water and air quality, and deter recreation because they are harmful to both human and animal health. Exposure to these toxins can occur through ingestion, inhalation, or skin contact. Acute health effects of HAB toxins have been well documented and include symptoms such as nausea, vomiting, abdominal pain and diarrhea, headache, fever, and skin rashes. While these adverse effects typically increase with amount, duration, and frequency of exposure, susceptibility to HAB toxins may also be increased by the presence of comorbidities. The emerging science on potential long-term or chronic effects of HAB toxins with a particular emphasis on microcystins, especially in vulnerable populations such as those with pre-existing liver or gastrointestinal disease, is summarized herein. This review suggests additional research is needed to define at-risk populations who may be helped by preventative measures. Furthermore, studies are required to develop a mechanistic understanding of chronic, low-dose exposure to HAB toxins so that appropriate preventative, diagnostic, and therapeutic strategies can be created in a targeted fashion.
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Affiliation(s)
- Apurva Lad
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Joshua D. Breidenbach
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Robin C. Su
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Jordan Murray
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Rebecca Kuang
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Alison Mascarenhas
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - John Najjar
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Shivani Patel
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Prajwal Hegde
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Mirella Youssef
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Jason Breuler
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Andrew L. Kleinhenz
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - Andrew P. Ault
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Judy A. Westrick
- Lumigen Instrumentation Center, Department of Chemistry, Wayne State University, Detroit, MI 48202, USA;
| | - Nikolai N. Modyanov
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
| | - David J. Kennedy
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
- Correspondence: (D.J.K.); (S.T.H.); Tel.: +1-419-383-6822 (D.J.K.); +1-419-383-6859 (S.T.H.)
| | - Steven T. Haller
- College of Medicine and Life Science, University of Toledo, Toledo, OH 43614, USA; (A.L.); (J.D.B.); (R.C.S.); (J.M.); (R.K.); (A.M.); (J.N.); (S.P.); (P.H.); (M.Y.); (J.B.); (A.L.K.); (N.N.M.)
- Correspondence: (D.J.K.); (S.T.H.); Tel.: +1-419-383-6822 (D.J.K.); +1-419-383-6859 (S.T.H.)
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Ishfaq PM, Mishra S, Mishra A, Ahmad Z, Gayen S, Jain SK, Tripathi S, Mishra SK. Inonotus obliquus aqueous extract prevents histopathological alterations in liver induced by environmental toxicant Microcystin. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2022; 3:100118. [PMID: 35992377 PMCID: PMC9389225 DOI: 10.1016/j.crphar.2022.100118] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 06/27/2022] [Accepted: 06/30/2022] [Indexed: 12/01/2022] Open
Abstract
Environmental toxicants like microcystins are known to adversely impact liver physiology and lead to the increased risk for abnormal liver function and even liver carcinoma. Chaga mushroom (Inonotus obliquus) is reported for various properties mainly antibacterial, antiallergic, anti-inflammatory, antioxidant, and anticancer properties. This study was aimed to assess the effect microcystin (MC-LR) on histopathology of liver in mice and a preventive measure by using aqueous extract of Inonotus obliquus (IOAE). Adult Balb/c mice were administered with MC-LR at 20 μg/kg body weight, per day, intraperitoneal (i.p.) for 4 weeks. IOAE was treated to one group of MC-LR mice at 200 mg/kg body weight, per oral, for 4 weeks. Histological staining for liver structural details and biochemical assays for functions were assessed. The results of the study showed that MC-LR drastically reduced the body weight of mice which were restored close to the range of control by IOAE treatment. MC-LR exposed mice showed 1.9, 1.7 and 2.2-fold increase in the levels of SGOT, SGPT and LDH which were restored by IOAE treatment as compared to control (one-fold). MC-LR exposed mice showed reduced level of GSH (19.83 ± 3.3 μM) which were regained by IOAE treatment (50.83 ± 3.0 μM). Similar observations were noted for catalase activity. Histological examinations show that MC-LR exposed degenerative changes in the liver sections which were restored by IOAE supplementation. The immunofluorescence analysis of caspase-3 counterstained with DAPI showed that MC-LR led to the increased expression of caspase-3 which were comparatively reduced by IOAE treatment. The cell viability decreased on increasing the concentration of MC-LR with 5% cell viability at concentration of 10 μg MC-LR/mL as that of control 100% Cell viability. The IC50 was calculated to be 3.6 μg/ml, indicating that MC-LR is chronic toxic to AML12 mouse hepatocytes. The molecular docking interaction of NF-κB-NIK with ergosterol peroxidase showed binding interaction between the two and showed the plausible molecular basis for the effects of IOAE in MC-LR induced liver injury. Collectively, this study revealed the deleterious effects of MC-LR on liver through generation of oxidative stress and activation of caspase-3, which were prevented by treatment with IOAE. Microcystin-LR is a potent hepatotoxic agent acting by inducing lipid peroxidation and oxidative damages. MC-LR exhibited significant deleterious alteration in liver by histopathological and biochemical signatures. Inonotus obliquus aqueous extract (IOAE) suppressed inflammation and oxidative damage in the liver induced by microcystin-LR. IOAE suppressed caspase-3 and p53 expression in MC-LR-induced liver. Chaga mushroom is suggested for using as a supplement in prevention of liver toxicity and inflammation.
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Affiliation(s)
- Pir Mohammad Ishfaq
- Cancer Biology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
- Molecular Biology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
| | - Shivani Mishra
- Cancer Biology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
| | - Anjali Mishra
- Cancer Biology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
| | - Zaved Ahmad
- Cancer Biology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
| | - Shovanlal Gayen
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
| | - Subodh Kumar Jain
- Molecular Biology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
| | - Swati Tripathi
- Amity Institute of Microbial Technology, Amity University, Noida, 201313, (U.P.), India
- Corresponding author.
| | - Siddhartha Kumar Mishra
- Cancer Biology Laboratory, Department of Zoology, School of Biological Sciences, Dr. Harisingh Gour Central University, Sagar, 470003, (M.P.), India
- Department of Biochemistry, University of Lucknow, Lucknow, 226007, (U.P.), India
- Corresponding author. Department of Biochemistry, University of Lucknow, Lucknow, 226007, (U.P.), India.
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Henri J, Lanceleur R, Delmas JM, Fessard V, Huguet A. Permeability of the Cyanotoxin Microcystin-RR across a Caco-2 Cells Monolayer. Toxins (Basel) 2021; 13:toxins13030178. [PMID: 33673481 PMCID: PMC7997155 DOI: 10.3390/toxins13030178] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 12/27/2022] Open
Abstract
Microcystins (MCs) are toxins produced by several cyanobacterial species found worldwide. While MCs have a common structure, the variation of two amino acids in their structure affects their toxicity. As toxicodynamics are very similar between the MC variants, their differential toxicity could rather be explained by toxicokinetic parameters. Microcystin-RR (MC-RR) is the second most abundant congener and induces toxicity through oral exposure. As intestinal permeability is a key parameter of oral toxicokinetics, the apparent permeability of MC-RR across a differentiated intestinal Caco-2 cell monolayer was investigated. We observed a rapid and large decrease of MC-RR levels in the donor compartment. However, irrespective of the loaded concentration and exposure time, the permeabilities were very low from apical to basolateral compartments (from 4 to 15 × 10−8 cm·s−1) and from basolateral to apical compartments (from 2 to 37 × 10−8 cm·s−1). Our results suggested that MC-RR would be poorly absorbed orally. As similar low permeability was reported for the most abundant congener microcystin-LR, and this variant presented a greater acute oral toxicity than MC-RR, we concluded that the intestinal permeability was probably not involved in the differential toxicity between them, in contrast to the hepatic uptake and metabolism.
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Chen G, Wang L, Wang M, Hu T. Comprehensive insights into the occurrence and toxicological issues of nodularins. MARINE POLLUTION BULLETIN 2021; 162:111884. [PMID: 33307402 DOI: 10.1016/j.marpolbul.2020.111884] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/01/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
The occurrence of cyanobacterial toxins is being increasingly reported. Nodularins (NODs) are one of the cyanotoxins group mainly produced by Nodularia spumigena throughout the world. NODs may exert adverse effects on animal and human health, and NOD-R variant is the most widely investigated. However, research focused on them is still limited. In order to understand the realistic risk well, the aim of this review is to compile the available information in the scientific literature regarding NODs, including their sources, distribution, structural characteristics, physicochemical properties, biosynthesis and degradation, adverse effects in vitro and vivo, and toxicokinetics. More data is urgently needed to integrate the cumulative or synergistic effects of NODs on different species and various cells to better understand, anticipate and aggressively manage their potential toxicity after both short- and long-term exposure in ecosystem, and to minimize or prevent the adverse effects on human health, environment and the economy.
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Affiliation(s)
- Guoliang Chen
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Linping Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Mingxing Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, China
| | - Tingzhang Hu
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, China.
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Biales AD, Bencic DC, Flick RW, Delacruz A, Gordon DA, Huang W. Global transcriptomic profiling of microcystin-LR or -RR treated hepatocytes (HepaRG). Toxicon X 2020; 8:100060. [PMID: 33235993 PMCID: PMC7670210 DOI: 10.1016/j.toxcx.2020.100060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 12/20/2022] Open
Abstract
The canonical mode of action (MOA) of microcystins (MC) is the inhibition of protein phosphatases, but complete characterization of toxicity pathways is lacking. The existence of over 200 MC congeners complicates risk estimates worldwide. This work employed RNA-seq to provide an unbiased and comprehensive characterization of cellular targets and impacted cellular processes of hepatocytes exposed to either MC-LR or MC-RR congeners. The human hepatocyte cell line, HepaRG, was treated with three concentrations of MC-LR or -RR for 2 h. Significant reduction in cell survival was observed in LR1000 and LR100 treatments whereas no acute toxicity was observed in any MR-RR treatment. RNA-seq was performed on all treatments of MC-LR and -RR. Differentially expressed genes and pathways associated with oxidative and endoplasmic reticulum (ER) stress, and the unfolded protein response (UPR) were highly enriched by both congeners as were inflammatory pathways. Genes associated with both apoptotic and inflammatory pathways were enriched in LR1000. We present a model of MC toxicity that immediately causes oxidative stress and leads to ER stress and the activation of the UPR. Differential activation of the three arms of the UPR and the kinetics of JNK activation ultimately determine whether cell survival or apoptosis is favored. Extracellular exosomes were enrichment of by both congeners, suggesting a previously unidentified mechanism for MC-dependent extracellular signaling. The complement system was enriched only in MC-RR treatments, suggesting congener-specific differences in cellular effects. This study provided an unbiased snapshot of the early systemic hepatocyte response to MC-LR and MC-RR congeners and may explain differences in toxicity among MC congeners. Microcystin-LR and microcystin-RR have similar transcriptional responses. Genes associated with oxidative stress and the unfolded protein response were enriched by congeners. Genes associated with extracellular exosomes were enriched, suggesting a potential new mechanism for cell signaling. Complement associated genes were strongly enriched only by microcystin-RR. Identified a potential molecular mechanism underlying the cellular fate of hepatocyte.
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Affiliation(s)
- Adam D Biales
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - David C Bencic
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Robert W Flick
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Armah Delacruz
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Denise A Gordon
- U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, USA
| | - Weichun Huang
- U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC, 27709, USA
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9
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Pappas D, Gkelis S, Panteris E. The effects of microcystin-LR in Oryza sativa root cells: F-actin as a new target of cyanobacterial toxicity. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:839-849. [PMID: 32268449 DOI: 10.1111/plb.13120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/26/2020] [Indexed: 05/26/2023]
Abstract
Microcystins are toxins produced by cyanobacteria, notorious for negatively affecting a wide range of living organisms, among which several plant species. Although microtubules are a well-established target of microcystin toxicity, its effect on filamentous actin (F-actin) in plant cells has not yet been studied. Τhe effects of microcystin-LR (MC-LR) and an extract of a microcystin-producing freshwater cyanobacterial strain (Microcystis flos-aquae TAU-MAC 1510) on the cytoskeleton (F-actin and microtubules) of Oryza sativa (rice) root cells were studied with light, confocal, and transmission electron microscopy. Considering the role of F-actin in endomembrane system distribution, the endoplasmic reticulum and the Golgi apparatus in extract-treated cells were also examined. F-actin in both MC-LR- and extract-treated meristematic and differentiating root cells exhibited time-dependent alterations, ranging from disorientation and bundling to the formation of ring-like structures, eventually resulting in a collapse of the F-actin network after longer treatments. Disorganization and eventual depolymerization of microtubules, as well as abnormal chromatin condensation were observed following treatment with the extract, effects which could be attributed to microcystins and other bioactive compounds. Moreover, cell cycle progression was inhibited in extract-treated roots, specifically affecting the mitotic events. As a consequence of F-actin network disorganization, endoplasmic reticulum elements appeared stacked and diminished, while Golgi dictyosomes appeared aggregated. These results support that F-actin is a prominent target of MC-LR, both in pure form and as an extract ingredient. Endomembrane system alterations can also be attributed to the effects of cyanobacterial bioactive compounds (including microcystins) on the F-actin cytoskeleton.
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Affiliation(s)
- D Pappas
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - S Gkelis
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - E Panteris
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
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10
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Beneficial Role of ROS in Cell Survival: Moderate Increases in H 2O 2 Production Induced by Hepatocyte Isolation Mediate Stress Adaptation and Enhanced Survival. Antioxidants (Basel) 2019; 8:antiox8100434. [PMID: 31581418 PMCID: PMC6826461 DOI: 10.3390/antiox8100434] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/07/2019] [Accepted: 09/17/2019] [Indexed: 01/06/2023] Open
Abstract
High levels of reactive oxygen species (ROS) can lead to impairment of cell structure, biomolecules' loss of function and cell death and are associated with liver diseases. Cells that survive increased ROS often undergo malignant transformation. Many cancer cells tolerate high levels of ROS. Here we report a transiently increased production of H2O2 and concomitant upregulation of antioxidative enzymes triggered by hepatocyte isolation; the H2O2 levels revert in about two days in culture. Three-day survival rate of the isolated cells in the presence of 2.5-fold increase of H2O2 is almost 80%. Apoptosis activation through the mitochondrial pathway is meanwhile reduced by inhibition of caspase-9 triggering. This reduction depends on the amount of H2O2 production, as decreased production of H2O2 in the presence of an antioxidant results in increased apoptosis triggering. These stress adaptations do not influence urea production, which is unchanged throughout the normal and stress adapted phases. We conclude that hepatocytes' stress adaptation is mediated by increased ROS production. In this case, high ROS improve cell survival.
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Basu A, Dydowiczová A, Čtveráčková L, Jaša L, Trosko JE, Bláha L, Babica P. Assessment of Hepatotoxic Potential of Cyanobacterial Toxins Using 3D In Vitro Model of Adult Human Liver Stem Cells. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10078-10088. [PMID: 30059226 DOI: 10.1021/acs.est.8b02291] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cyanotoxins microcystin-LR (MC-LR) and cylindrospermopsin (CYN) represent hazardous waterborne contaminants and potent human hepatotoxins. However, in vitro monolayer cultures of hepatic cell lines were found to recapitulate, poorly, major hepatocyte-specific functions and inadequately predict hepatotoxic effects of MC-LR and CYN. We utilized 3-dimensional (3D), scaffold-free spheroid cultures of human telomerase-immortalized adult liver stem cells HL1-hT1 to evaluate hepatotoxic potential of MC-LR and CYN. In monolayer cultures of HL1-hT1 cells, MC-LR did not induce cytotoxic effects (EC50 > 10 micromol/L), while CYN inhibited cell growth and viability (48h-96h EC50 ≈ 5.5-0.6 micromol/L). Growth and viability of small growing spheroids were inhibited by both cyanotoxins (≥0.1 micromol/L) and were associated with blebbing and disintegration at the spheroid surface. Hepatospheroid damage and viability reduction were observed also in large mature spheroids, with viability 96h-EC50 values being 0.04 micromol/L for MC-LR and 0.1 micromol/L for CYN, and No Observed Effect Concentrations <0.01 micromol/L. Spheroid cultures of adult human liver stem cells HL1-hT1 exhibit sensitivity comparable to cultures of primary hepatocytes and provide a simple, practical, and cost-effective tool, which can be effectively used in environmental and toxicological research, including assessment of hepatotoxic potential and effect-based monitoring of various samples contaminated with toxic cyanobacteria.
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Affiliation(s)
- Amrita Basu
- RECETOX, Faculty of Science , Masaryk University , Kamenice 753/5 , Brno 625 00 , Czech Republic
| | - Aneta Dydowiczová
- RECETOX, Faculty of Science , Masaryk University , Kamenice 753/5 , Brno 625 00 , Czech Republic
| | - Lucie Čtveráčková
- RECETOX, Faculty of Science , Masaryk University , Kamenice 753/5 , Brno 625 00 , Czech Republic
| | - Libor Jaša
- RECETOX, Faculty of Science , Masaryk University , Kamenice 753/5 , Brno 625 00 , Czech Republic
| | - James E Trosko
- Department of Pediatrics and Human Development & Institute for Integrative Toxicology , Michigan State University , 1129 Farm Lane , East Lansing , 48824 Michigan , United States
| | - Luděk Bláha
- RECETOX, Faculty of Science , Masaryk University , Kamenice 753/5 , Brno 625 00 , Czech Republic
| | - Pavel Babica
- RECETOX, Faculty of Science , Masaryk University , Kamenice 753/5 , Brno 625 00 , Czech Republic
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12
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Huang P, Wang S, Weng D, Xu L. Alpha4-overexpressing HL7702 cells can counteract microcystin-LR effects on cytoskeletal structure. ENVIRONMENTAL TOXICOLOGY 2018; 33:978-987. [PMID: 29984889 DOI: 10.1002/tox.22585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/28/2018] [Accepted: 05/28/2018] [Indexed: 06/08/2023]
Abstract
Our previous studies indicated that α4 was involved in the toxicity of MC-LR on the cytoskeleton via the change of PP2A activity in HEK 293. To explore the role of α4 in MC-LR toxicity via PP2A regulation in different cell lines, the HL7702 cell overexpressing α4 protein was exposed to MC-LR, and the change of PP2A, cytoskeletal structure, and cytoskeleton-related proteins were investigated. The results showed that PP2A activity was decreased, PP2A/C subunit expression and phosphorylation (Tyr307) increased significantly, but methylation (Leu 309)clearly decreased. The structure of the actin filaments and microtubules (MTs) remained unchanged, and the expression and phosphorylation of the cytoskeleton-related proteins showed different changes. In addition, the main components of the MAPK pathway, JNK, P38, and ERK1/2, were activated together. Our results indicated that elevated α4 expression did confer some resistance to MC-LR-induced cytoskeletal changes, but the responses of different cell lines to MC-LR, under the α4-overexpression condition, are not exactly the same.
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Affiliation(s)
- Pu Huang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Sha Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Dengpo Weng
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
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13
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Rodrigues Pires Júnior O, de Oliveira NB, Bosque RJ, Nice Ferreira MF, Morais Aurélio da Silva V, Martins Magalhães AC, Correia de Santana CJ, de Souza Castro M. Histopathological Evaluation of the Exposure by Cyanobacteria Cultive Containing [d-Leu¹]Microcystin-LR on Lithobates catesbeianus Tadpoles. Toxins (Basel) 2018; 10:toxins10080318. [PMID: 30082615 PMCID: PMC6116141 DOI: 10.3390/toxins10080318] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/21/2018] [Accepted: 07/24/2018] [Indexed: 01/28/2023] Open
Abstract
This study evaluated the effects of [d-Leu1]Microcystin-LR variant by the exposure of Lithobates catesbeianus tadpole to unialgal culture Microcystis aeruginosa NPLJ-4 strain. The Tadpole was placed in aquariums and exposed to Microcystis aeruginosa culture or disrupted cells. For 16 days, 5 individuals were removed every 2 days, and tissue samples of liver, skeletal muscle, and intestinal tract were collected for histopathology and bioaccumulation analyses. After exposure, those surviving tadpoles were placed in clean water for 15 days to evaluate their recovery. A control without algae and toxins was maintained in the same conditions and exhibited normal histology and no tissue damage. In exposed tadpoles, samples were characterized by serious damages that similarly affected the different organs, such as loss of adhesion between cells, nucleus fragmentation, necrosis, and hemorrhage. Samples showed signs of recovery but severe damages were still observed. Neither HPLC-PDA nor mass spectrometry analysis showed any evidence of free Microcystins bioaccumulation.
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Affiliation(s)
- Osmindo Rodrigues Pires Júnior
- Toxinology Laboratory, Depto. Physiological Sciences, Institute of Biology, University of Brasilia, Brasilia 70910-900, Brazil.
| | - Natiela Beatriz de Oliveira
- Toxinology Laboratory, Depto. Physiological Sciences, Institute of Biology, University of Brasilia, Brasilia 70910-900, Brazil.
| | - Renan J Bosque
- Depto. Genetics and Morphology, Institute of Biology, University of Brasilia, Brasilia 70910-900, Brazil.
| | | | | | - Ana Carolina Martins Magalhães
- Toxinology Laboratory, Depto. Physiological Sciences, Institute of Biology, University of Brasilia, Brasilia 70910-900, Brazil.
| | - Carlos José Correia de Santana
- Toxinology Laboratory, Depto. Physiological Sciences, Institute of Biology, University of Brasilia, Brasilia 70910-900, Brazil.
| | - Mariana de Souza Castro
- Toxinology Laboratory, Depto. Physiological Sciences, Institute of Biology, University of Brasilia, Brasilia 70910-900, Brazil.
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Exposure routes and health effects of microcystins on animals and humans: A mini-review. Toxicon 2018; 151:156-162. [PMID: 30003917 DOI: 10.1016/j.toxicon.2018.07.010] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 07/04/2018] [Accepted: 07/08/2018] [Indexed: 02/03/2023]
Abstract
Microcystins (MCs) pollution has quickly risen in infamy and has become a major problem to public health worldwide. MCs are a group of monocyclic hepatotoxic peptides, which are produced by some bloom-forming cyanobacteria in water. More than 100 different MCs variants posing a great threat to animals and humans due to their potential carcinogenicity have been reported. To reduce MCs risks, the World Health Organization has set a provisional guideline of 1 μg/L MCs in human's drinking water. This paper provides an overview of exposure routes of MCs into the human system and health effects on different organs after MCs exposure including the liver, intestine, brain, kidney, lung, heart and reproductive system. In addition, some evidences on human poisoning and deaths associated with MCs exposure are presented. Finally, in order to protect human life against the health threats posed by MCs, this paper also suggests some directions for future research that can advance MCs control and minimize human exposure to MCs.
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15
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Tumor-promoting cyanotoxin microcystin-LR does not induce procarcinogenic events in adult human liver stem cells. Toxicol Appl Pharmacol 2018. [PMID: 29534881 DOI: 10.1016/j.taap.2018.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
HL1-hT1 cell line represents adult human liver stem cells (LSCs) immortalized with human telomerase reverse transcriptase. In this study, HL1-hT1 cells were found to express mesenchymal markers (vimentin, CD73, CD90/THY-1 and CD105) and an early hepatic endoderm marker FOXA2, while not expressing hepatic progenitor (HNF4A, LGR5, α-fetoprotein) or differentiated hepatocyte markers (albumin, transthyretin, connexin 32). In response to microcystin-LR (MC-LR), a time- and concentration-dependent formation of MC-positive protein bands in HL1-hT1 cells was observed. Cellular accumulation of MC-LR occurred most likely via mechanisms independent on organic anion transporting polypeptides (OATPs) or multidrug resistance (MDR) proteins, as indicated (a) by a gene expression analysis of 11 human OATP genes and 4 major MDR genes (MDR1/P-glycoprotein, MRP1, MRP2 and BCRP); (b) by non-significant effects of OATP or MDR1 inhibitors on MC-LR uptake. Accumulation of MC-positive protein bands in HL1-hT1 cells was associated neither with alterations of cell viability and growth, dysregulations of ERK1/2 and p38 kinases, reactive oxygen species formation, induction of double-stranded DNA breaks nor modulations of stress-inducible genes (ATF3, HSP5). It suggests that LSCs might have a selective, MDR1-independent, survival advantage and higher tolerance towards MC-induced cytotoxic, genotoxic or cancer-related events than differentiated adult hepatocytes, fetal hepatocyte or malignant liver cell lines. HL1-hT1 cells provide a valuable in vitro tool for studying effects of toxicants and pharmaceuticals on LSCs, whose important role in the development of chronic toxicities and liver diseases is being increasingly recognized.
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Wang B, Liu J, Huang P, Xu K, Wang H, Wang X, Guo Z, Xu L. Protein phosphatase 2A inhibition and subsequent cytoskeleton reorganization contributes to cell migration caused by microcystin-LR in human laryngeal epithelial cells (Hep-2). ENVIRONMENTAL TOXICOLOGY 2017; 32:890-903. [PMID: 27393157 DOI: 10.1002/tox.22289] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 05/08/2016] [Accepted: 05/08/2016] [Indexed: 06/06/2023]
Abstract
The major toxic mechanism of Microcystin-LR is inhibition of the activity of protein phosphatase 2A (PP2A), resulting in a series of cytotoxic effects. Our previous studies have demonstrated that microcystin-LR (MCLR) induced very different molecular effects in normal cells and the tumor cell line SMMC7721. To further explore the MCLR toxicity mechanism in tumor cells, human laryngeal epithelial cells (Hep-2) was examined in this study. Western blot, immunofluorescence, immunoprecipitation, and transwell migration assay were used to detect the effects of MCLR on PP2A activity, PP2A substrates, cytoskeleton, and cell migration. The results showed that the protein level of PP2A subunits and the posttranslational modification of the catalytic subunit were altered and that the binding of the AC core enzyme as well as the binding of PP2A/C and α4, was also affected. As PP2A substrates, the phosphorylation of MAPK pathway members, p38, ERK1/2, and the cytoskeleton-associated proteins, Hsp27, VASP, Tau, and Ezrin were increased. Furthermore, MCLR induced reorganization of the cytoskeleton and promoted cell migration. Taken together, direct covalent binding to PP2A/C, alteration of the protein levels and posttranslational modification, as well as the binding of subunits, are the main pattern for the effects of MCLR on PP2A in Hep-2. A dose-dependent change in p-Tau and p-Ezrin due to PP2A inhibition may contribute to the changes in the cytoskeleton and be related to the cell migration in Hep-2. Our data provide a comprehensive exposition of the MCLR mechanism on tumor cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 890-903, 2017.
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Affiliation(s)
- Beilei Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Jinghui Liu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Pu Huang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Kailun Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Hanying Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Xiaofeng Wang
- Zhejiang Center for Disease Control and Prevention, Hangzhou, 310051, China
| | - Zonglou Guo
- Department of Biosystem Engineering, College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
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Lee J, Lee S, Jiang X. Cyanobacterial Toxins in Freshwater and Food: Important Sources of Exposure to Humans. Annu Rev Food Sci Technol 2017; 8:281-304. [PMID: 28245155 DOI: 10.1146/annurev-food-030216-030116] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A recent ecological study demonstrated a significant association between an increased risk of nonalcoholic liver disease mortality and freshwater cyanobacterial blooms. Moreover, previous epidemiology studies highlighted a relationship between cyanotoxins in drinking water with liver cancer and damage and colorectal cancer. These associations identified cyanobacterial blooms as a global public health and environmental problem, affecting freshwater bodies that are important sources for drinking water, agriculture, and aquafarms. Furthermore, as a result of climate change, it is expected that our freshwater environments will become more favorable for producing harmful blooms that produce various cyanotoxins. Food is an important source of cyanotoxin exposure to humans, but it has been less addressed. This paper synthesizes information from the studies that have investigated cyanotoxins in freshwater and food on a global scale. We also review and summarize the health effects and exposure routes of cyanotoxins and candidates for cyanotoxin treatment methods that can be applied to food.
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Affiliation(s)
- Jiyoung Lee
- Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH 43210; .,Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210; .,Environmental Science Graduate Program, The Ohio State University, Columbus, OH 43210;
| | - Seungjun Lee
- Environmental Science Graduate Program, The Ohio State University, Columbus, OH 43210;
| | - Xuewen Jiang
- Department of Food Science and Technology, The Ohio State University, Columbus, OH 43210;
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18
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Microcystin-LR induced liver injury in mice and in primary human hepatocytes is caused by oncotic necrosis. Toxicon 2016; 125:99-109. [PMID: 27889601 DOI: 10.1016/j.toxicon.2016.11.254] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 11/16/2016] [Accepted: 11/22/2016] [Indexed: 11/22/2022]
Abstract
Microcystins are a group of toxins produced by freshwater cyanobacteria. Uptake of microcystin-leucine arginine (MC-LR) by organic anion transporting polypeptide 1B2 in hepatocytes results in inhibition of protein phosphatase 1A and 2A, and subsequent cell death. Studies performed in primary rat hepatocytes demonstrate prototypical apoptosis after MC-LR exposure; however, no study has directly tested whether apoptosis is critically involved in vivo in the mouse, or in human hepatocytes. MC-LR (120 μg/kg) was administered to C57BL/6J mice and cell death was evaluated by alanine aminotransferase (ALT) release, caspase-3 activity in the liver, and histology. Mice exposed to MC-LR had increases in plasma ALT values, and hemorrhage in the liver, but no increase in capase-3 activity in the liver. Pre-treatment with the pan-caspase inhibitor z-VAD-fmk failed to protect against cell death measured by ALT, glutathione depletion, or hemorrhage. Administration of MC-LR to primary human hepatocytes resulted in significant toxicity at concentrations between 5 nM and 1 μM. There were no elevated caspase-3 activities and pretreatment with z-VAD-fmk failed to protect against cell death in human hepatocytes. MC-LR treated human hepatocytes stained positive for propidium iodide, indicating membrane instability, a marker of necrosis. Of note, both increases in PI positive cells, and increases in lactate dehydrogenase release, occurred before the onset of complete actin filament collapse. In conclusion, apoptosis does not contribute to MC-LR-induced cell death in the in vivo mouse model or in primary human hepatocytes in vitro. Thus, targeting necrotic cell death mechanisms will be critical for preventing microcystin-induced liver injury.
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Bulc Rozman K, Jurič DM, Šuput D. Selective cytotoxicity of microcystins LR, LW and LF in rat astrocytes. Toxicol Lett 2016; 265:1-8. [PMID: 27864109 DOI: 10.1016/j.toxlet.2016.11.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/08/2016] [Accepted: 11/14/2016] [Indexed: 12/24/2022]
Abstract
Microcystins (MCs) comprise a group of cyanobacterial toxins with hepatotoxic, nephrotoxic and, possibly, neurotoxic activity in mammals. In order to understand the development of their neurotoxicity we investigated the toxic effects of MC variants, MC-LR, MC-LW and MC-LF, in astrocytes that play a central role in maintaining brain homeostasis. 24h exposure of cultured rat cortical astrocytes to MCs revealed dose-dependent toxicity of MC-LF and MC-LW, but not of MC-LR, observed by significant reduction in cell number, declined viability monitored by MTT test and an increased percentage of apoptotic cells, confirmed by Annexin-V labelling. The cultured astrocytes expressed organic anion-transporting polypeptides (Oatp) Oatp1a4, Oatp1c1 and Oatp1a5, but not Oatp1b2. Intracellular localisation of MC-LF and MC-LW, proven by anti-Adda primary antibody, demonstrated transport of tested MCs into cultured astrocytes. Acute MC-LW and MC-LF intoxication induced cytoskeletal disruption as seen by the degradation of glial fibrillary acid protein (GFAP), actin and the tubulin network. In this in vitro study, MC-LF and MC-LW, but not MC-LR, are shown to cause the dysfunction of astrocytic homeostatic capabilities, already at low concentrations, suggesting that astrocyte atrophy, with loss of function, could be expected in the brain response to the toxic insult.
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Affiliation(s)
- Klara Bulc Rozman
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, Ljubljana, Slovenia.
| | - Damijana Mojca Jurič
- Institute of Pharmacology and Experimental Toxicology, Faculty of Medicine, University of Ljubljana, Korytkova 2, Ljubljana, Slovenia.
| | - Dušan Šuput
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, Ljubljana, Slovenia.
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20
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Clark SP, Davis MA, Ryan TP, Searfoss GH, Hooser SB. Hepatic Gene Expression Changes in Mice Associated with Prolonged Sublethal Microcystin Exposure. Toxicol Pathol 2016; 35:594-605. [PMID: 17654400 DOI: 10.1080/01926230701383210] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Microcystin-LR (MCLR) is an acute hepatotoxicant and suspected carcinogen. Previous chronic studies have individually described hepatic morphologic changes, or alterations in the cytoskeleton, cell signaling or redox pathways. The objective of this study was to characterize chronic effects of MCLR in wild-type mice utilizing gene array analysis, morphology, and plasma chemistries. MCLR was given daily for up to 28 days. RNA from the 28-day study was hybridized onto mouse genechip arrays. RNA from 4 hours, 24 hours, 4 days, 1 day, and 28 days for selected genes was processed for quantitative-PCR. Increases in plasma hepatic enzyme activities and decreases in total protein, albumin and glucose concentrations were identified in MCLR-treated groups at 14 and 28 days. Histologically, marked hepatokaryomegaly was identified in the 14-day MCLR group with the addition of giant cells at 28 days. Major gene transcript changes were identified in the actin organization, cell cycle, apoptotic, cellular redox, cell signaling, albumin metabolism, and glucose homeostasis pathways, and the organic anion transport polypeptide system. Using toxicogenomics, we have identified key molecular pathways involved in chronic sublethal MCLR exposure in wild-type mice, genes participating in those critical pathways and related them to cellular and morphologic alterations seen in this and other studies.
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Affiliation(s)
- Shawn P Clark
- Department of Veterinary Pathobiology, Purdue University, Indiana 47907, USA.
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Meili N, Christen V, Fent K. Nodularin induces tumor necrosis factor-alpha and mitogen-activated protein kinases (MAPK) and leads to induction of endoplasmic reticulum stress. Toxicol Appl Pharmacol 2016; 300:25-33. [DOI: 10.1016/j.taap.2016.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 03/23/2016] [Accepted: 03/26/2016] [Indexed: 01/08/2023]
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22
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Valério E, Campos A, Osório H, Vasconcelos V. Proteomic and Real-Time PCR analyses of Saccharomyces cerevisiae VL3 exposed to microcystin-LR reveals a set of protein alterations transversal to several eukaryotic models. Toxicon 2016; 112:22-8. [PMID: 26806210 DOI: 10.1016/j.toxicon.2016.01.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 01/16/2016] [Accepted: 01/20/2016] [Indexed: 02/01/2023]
Abstract
Some of the most common toxins present in freshwater, in particular microcystins (MCs), are produced by cyanobacteria. These toxins have a negative impact on human health, being associated with episodes of acute hepatotoxicity and being considered potentially carcinogenic to humans. To date the exact mechanisms of MC-induced toxicity and tumor promotion were not completely elucidated. To get new insights underlying microcystin-LR (MCLR) molecular mechanisms of toxicity we have performed the proteomic profiling using two-dimensional electrophoresis and MALDI-TOF/TOF of Saccharomyces cerevisiae cells exposed for 4 h-1 nM and 1 μM of MCLR, and compared them to the control (cells not exposed to MCLR). We identified 14 differentially expressed proteins. The identified proteins are involved in metabolism, genotoxicity, cytotoxicity and stress response. Furthermore, we evaluated the relative expression of yeast's PP1 and PP2A genes and also of genes from the Base Excision Repair (BER) DNA-repair system, and observed that three out of the five genes analyzed displayed dose-dependent responses. Overall, the different proteins and genes affected are related to oxidative stress and apoptosis, thus reinforcing that it is probably the main mechanism of MCLR toxicity transversal to several organisms, especially at lower doses. Notwithstanding these MCLR responsive proteins could be object of further studies to evaluate their suitability as biomarkers of exposure to the toxin.
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Affiliation(s)
- Elisabete Valério
- Unidade de Água e Solo, Departamento de Saúde Ambiental, Instituto Nacional de Saúde Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016, Lisboa, Portugal; Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal.
| | - Alexandre Campos
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal
| | - Hugo Osório
- IPATIMUP - Institute of Molecular Pathology and Immunology of the University of Porto, 4200-465, Porto, Portugal; Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal
| | - Vitor Vasconcelos
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas 289, 4050-123, Porto, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4069-007, Porto, Portugal
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Zeng J, Tu WW, Lazar L, Chen DN, Zhao JS, Xu J. Hyperphosphorylation of microfilament-associated proteins is involved in microcystin-LR-induced toxicity in HL7702 cells. ENVIRONMENTAL TOXICOLOGY 2015; 30:981-988. [PMID: 24677693 DOI: 10.1002/tox.21974] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 02/05/2014] [Accepted: 02/09/2014] [Indexed: 06/03/2023]
Abstract
Microcystin-LR (MC-LR) has been regarded as a hepatotoxin, which can cause cytoskeletal reorganization, especially of the actin filaments. However, the underlying mechanisms remain unclear. In this study, whether MC-LR could induce microfilaments disruption was verified in the normal human liver cell line HL7702; and then the transcription, translation, and phosphorylation levels of major microfilament-associated proteins were measured; finally, the underlying mechanisms was investigated. After treatment with MC-LR, the actin filaments lost their characteristic filamentous organization in the cells, demonstrating increased actin depolymerization. The mRNA and protein levels of ezrin, vasodilator-stimulated phosphoprotein (VASP), actin-related protein2/3, and cofilin remained unchanged. However, the phosphorylation levels of ezrin and VASP were increased, when treated with 10 μM MC-LR. Moreover, P38 and ERK1/2 were involved in MC-LR-induced hyperphosphorylation of microfilament-associated proteins. In summary, this study demonstrates that MC-LR can cause disruption of actin filaments in HL7702 cells due to MC-LR-induced mitogen-activated protein kinase pathway activation and hyperphosphorylation of different types of microfilament-associated proteins.
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Affiliation(s)
- Jing Zeng
- Department of Preventive Medicine, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Wei-Wei Tu
- Department of Preventive Medicine, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Lissy Lazar
- Department of Preventive Medicine, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Dong-Ni Chen
- Department of Preventive Medicine, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Jin-Shun Zhao
- Department of Preventive Medicine, School of Medicine, Ningbo University, Ningbo, 315211, China
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Jin Xu
- Department of Preventive Medicine, School of Medicine, Ningbo University, Ningbo, 315211, China
- Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
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24
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Mechanisms of microcystin-LR-induced cytoskeletal disruption in animal cells. Toxicon 2015; 101:92-100. [DOI: 10.1016/j.toxicon.2015.05.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 05/06/2015] [Accepted: 05/12/2015] [Indexed: 12/31/2022]
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25
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Ufelmann H, Schrenk D. Nodularin-triggered apoptosis and hyperphosphorylation of signaling proteins in cultured rat hepatocytes. Toxicol In Vitro 2015; 29:16-26. [DOI: 10.1016/j.tiv.2014.08.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 01/18/2023]
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26
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Sun Y, Liu JH, Huang P, Guo ZL, Xu LH. Alterations of tau and VASP during microcystin-LR-induced cytoskeletal reorganization in a human liver cell line. ENVIRONMENTAL TOXICOLOGY 2015; 30:92-100. [PMID: 23929704 DOI: 10.1002/tox.21898] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 07/04/2013] [Accepted: 07/11/2013] [Indexed: 06/02/2023]
Abstract
Previously, we have reported alterations to HSP27 during Microcystin-LR (MC-LR)-induced cytoskeletal reorganization in the human liver cell line HL7702. To further elucidate the detailed mechanism of MC-LR-induced cytoskeletal assembly, we focused on two cytoskeletal-related proteins, Tau and VASP. These two proteins phosphorylated status influences their ability to bind and stabilize cytoskeleton. We found that MC-LR markedly increased the level of Tau phosphorylation with the dissociation of phosphorylated Tau from the cytoskeleton. Furthermore, the phosphorylation of Tau induced by MC-LR was suppressed by an activator of PP2A and by an inhibitor of p38 MAPK. VASP was also hyperphosphorylated upon MC-LR exposure; however, its phosphorylation appeared to regulate its cellular localization rather than cytoskeletal dynamics, and its phosphorylation was unaffected by the PP2A activator. These data suggest that phosphorylated Tau is regulated by p38 MAPK, possibly as a consequence of PP2A inhibition. Tau hyperphosphorylation is likely an important factor leading to the cytoskeletal destabilization triggered by MC-LR and the role of VASP alteration upon MC-LR exposure needs to be studied further. To our knowledge, the finding that Tau is implicated in cytoskeletal destabilization in MC-LR-treated hepatocytes and MC-LR-induced VASP's alteration has not been reported previously.
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Affiliation(s)
- Yu Sun
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, People's Republic of China
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27
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Sun Y, Zheng Q, Sun YT, Huang P, Guo ZL, Xu LH. Microcystin-LR induces protein phosphatase 2A alteration in a human liver cell line. ENVIRONMENTAL TOXICOLOGY 2014; 29:1236-1244. [PMID: 23436320 DOI: 10.1002/tox.21854] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 01/09/2013] [Accepted: 01/17/2013] [Indexed: 06/01/2023]
Abstract
Microcystin-LR (MC-LR) is a potent inhibitor of protein phosphatases 1 and 2A, and has potent hepatotoxicity and tumor promotion activity. Numerous studies on MC-LR toxicity have been conducted in rat hepatocytes, but few studies of the effects of microcystins on human hepatocytes have been done. In this study, HL7702 cells (a human normal liver cell line) were incubated in MC-LR for 24 h. The existence of MC-LR in HL7702 cells was confirmed. Furthermore, PP2A activity and the alteration of PP2A subunits were assessed. The results show that PP2A activity decreased from the concentration of 1 μM MC-LR, showing a concentration-dependent decline, to about 34% at 10 μM MC-LR. This activity undergone opposite change with alternations of phosphorylated Y307-PP2A/C and PP2A/C subunit but showed same change with the alteration of the ratio of methylated L309-PP2A/C to PP2A/C. B55α, a regulatory subunit of PP2A, was slightly increases in cells treated with the highest concentration of MC-LR (10 μM), and colocalized increasedly with rearranged-microtubules after 1 μM MC-LR exposure. However, the proportion of early apoptotic cells did not show any change at various concentration of MC-LR for 24 h. To our knowledge, this is the first report showing MC-LR-induced alteration of PP2A phosphatase in human cultured hepatocytes, and the mechanism of action seems to be similar as described before in vitro. The alteration of PP2A and microtubule seems to be the early event induced by MC-LR exposure.
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Affiliation(s)
- Yu Sun
- Department of Biochemistry and Molecular Biology, School of Medicine, Zhejiang University, 310058 Hangzhou, China
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28
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Low in vitro permeability of the cyanotoxin microcystin-LR across a Caco-2 monolayer: with identification of the limiting factors using modelling. Toxicon 2014; 91:5-14. [PMID: 25110175 DOI: 10.1016/j.toxicon.2014.07.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 01/25/2023]
Abstract
Microcystins (MCs) are toxins produced by several cyanobacteria species found worldwide. MC-LR is the most frequent. Here, we used the human Caco-2 cell line grown on semi-permeable filter supports as an in vitro model for determining MC-LR intestinal bidirectional transport. In this study, there was very low and time-dependent apparent permeability of MC-LR. To identify the limiting factors involved in the low permeability of MC-LR, a mathematical model was constructed to get physiologically relevant and informative parameters. The apical-to-basolateral transport was characterised by a rapid and substantial decrease in apical MC-LR concentrations (24-40% of the initial amount). In the basolateral compartment, the concentrations increased slowly after a lag time, but represented only a small fraction of the loaded concentrations (0.3-1.3%) after 24 h. This weak permeability was mainly due to a low clearance of efflux (from the cellular to the basolateral compartment) and effective secretion (from the cellular to the apical compartment). During the basolateral-to-apical transport, we observed a slow decrease in basolateral concentrations and a rapid increase in apical concentrations. In conclusion, modelling has the potential to highlight the key mechanisms involved in the complex kinetics of toxin transport.
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29
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Surface-enhanced fluorescence immunosensor using Au nano-crosses for the detection of microcystin-LR. Biosens Bioelectron 2014; 62:255-60. [PMID: 25016333 DOI: 10.1016/j.bios.2014.06.064] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/27/2014] [Accepted: 06/30/2014] [Indexed: 01/12/2023]
Abstract
A surface-enhanced fluorescence (SEF) immunosensor for the detection of microcystin-LR was developed using Au nano-crosses as fluorescence enhancement nanoparticles and cy5 as a fluorescence label molecule. The SEF effects of cy5 in the proximity of Au nanorods and gold nano-crosses was investigated by using Au nanorods or nano-crosses coated negative-charged glass surfaces. Fluorescence measurements indicated that SEF was influenced by the size, shape and distribution of the Au nanoparticles, with an appropriate spacer layer between the Au nanoparticles and the cy5. The enhancement factor was from 2.3- to 35-fold. Under optimal conditions, the SEF immunosensor exhibited a good linear response at microcystin-LR concentrations of 0.02-16 ng mL(-1) (R(2)=0.9981). The limit of detection was 0.007 ng mL(-1) with little adsorption of microcystin-RR, microcystin-LW, and microcystin-LF. High microcystin-LR recoveries were obtained from naturally contaminated fish samples. The SEF immunosensor allows the reliable detection of microcystin-LR in seafood, and has potential in simple, sensitive detection applications.
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30
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Genotoxicity of microcystin-LR in in vitro and in vivo experimental models. BIOMED RESEARCH INTERNATIONAL 2014; 2014:949521. [PMID: 24955368 PMCID: PMC4052155 DOI: 10.1155/2014/949521] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/30/2014] [Indexed: 01/21/2023]
Abstract
Microcystin-LR (MCLR) is a cyanobacterial toxin known for its acute hepatotoxicity. Despite being recognized as tumour promoter, its genotoxicity is far from being completely clarified, particularly in organs other than liver. In this work, we used the comet and/or the micronucleus (MN) assays to study the genotoxicity of MCLR in kidney- (Vero-E6) and liver-derived (HepG2) cell lines and in blood cells from MCLR-exposed mice. MCLR treatment (5 and 20 μM) caused a significant induction in the MN frequency in both cell lines and, interestingly, a similar positive effect was observed in mouse reticulocytes (37.5 μg MCLR/kg, i.p. route). Moreover, the FISH-based analysis of the MN content (HepG2 cells) suggested that MCLR induces both chromosome breaks and loss. On the other hand, the comet assay results were negative in Vero-E6 cells and in mouse leukocytes, with the exception of a transient increase in the level of DNA damage 30 minutes after mice exposure. Overall, the present findings contributed to increase the weight of evidence in favour of MCLR genotoxicity, based on its capacity to induce permanent genetic damage either in vitro or in vivo. Moreover, they suggest a clastogenic and aneugenic mode of action that might underlie a carcinogenic effect.
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31
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Kozdęba M, Borowczyk J, Zimoląg E, Wasylewski M, Dziga D, Madeja Z, Drukala J. Microcystin-LR affects properties of human epidermal skin cells crucial for regenerative processes. Toxicon 2014; 80:38-46. [DOI: 10.1016/j.toxicon.2014.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 01/03/2014] [Accepted: 01/09/2014] [Indexed: 11/29/2022]
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32
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Milutinović A, Zorc-Pleskovič R, Živin M, Vovk A, Seša I, Šuput D. Magnetic resonance imaging for rapid screening for the nephrotoxic and hepatotoxic effects of microcystins. Mar Drugs 2013; 11:2785-98. [PMID: 23921723 PMCID: PMC3766865 DOI: 10.3390/md11082785] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/04/2013] [Accepted: 07/19/2013] [Indexed: 01/08/2023] Open
Abstract
In vivo visualization of kidney and liver damage by Magnetic Resonance Imaging (MRI) may offer an advantage when there is a need for a simple, non-invasive and rapid method for screening of the effects of potential nephrotoxic and hepatotoxic substances in chronic experiments. Here, we used MRI for monitoring chronic intoxication with microcystins (MCs) in rat. Male adult Wistar rats were treated every other day for eight months, either with MC-LR (10 μg/kg i.p.) or MC-YR (10 μg/kg i.p.). Control groups were treated with vehicle solutions. T1-weighted MR-images were acquired before and at the end of the eight months experimental period. Kidney injury induced by the MCs presented with the increased intensity of T1-weighted MR-signal of the kidneys and liver as compared to these organs from the control animals treated for eight months, either with the vehicle solution or with saline. The intensification of the T1-weighted MR-signal correlated with the increased volume density of heavily injured tubuli (R2 = 0.77), with heavily damaged glomeruli (R2 = 0.84) and with volume density of connective tissue (R2 = 0.72). The changes in the MR signal intensity probably reflect the presence of an abundant proteinaceous material within the dilated nephrons and proliferation of the connective tissue. T1-weighted MRI-is a valuable method for the in vivo screening of kidney and liver damage in rat models of intoxication with hepatotoxic and nephrotoxic agents, such as microcystins.
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Affiliation(s)
- Aleksandra Milutinović
- Institute of Histology and Embryology, Faculty of Medicine, University of Ljubljana, Korytkova 2, Ljubljana 1000, Slovenia; E-Mails: (A.M.); (R.Z.-P.)
| | - Ruda Zorc-Pleskovič
- Institute of Histology and Embryology, Faculty of Medicine, University of Ljubljana, Korytkova 2, Ljubljana 1000, Slovenia; E-Mails: (A.M.); (R.Z.-P.)
| | - Marko Živin
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana 1000, Slovenia; E-Mails: (M.Z.); (A.V.)
| | - Andrej Vovk
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana 1000, Slovenia; E-Mails: (M.Z.); (A.V.)
- Centre for Clinical Physiology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, Ljubljana 1000, Slovenia
| | - Igor Seša
- Institute Jožef Stefan, Jamova 23, Ljubljana 1000, Slovenia; E-Mail:
| | - Dušan Šuput
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, Ljubljana 1000, Slovenia; E-Mails: (M.Z.); (A.V.)
- Centre for Clinical Physiology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, Ljubljana 1000, Slovenia
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Chen DN, Zeng J, Wang F, Zheng W, Tu WW, Zhao JS, Xu J. Hyperphosphorylation of intermediate filament proteins is involved in microcystin-LR-induced toxicity in HL7702 cells. Toxicol Lett 2012; 214:192-9. [DOI: 10.1016/j.toxlet.2012.08.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 08/24/2012] [Accepted: 08/25/2012] [Indexed: 12/11/2022]
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Microcystin (-LR) affects hormones level of male mice by damaging hypothalamic-pituitary system. Toxicon 2012; 59:205-14. [DOI: 10.1016/j.toxicon.2011.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 11/29/2011] [Accepted: 12/01/2011] [Indexed: 11/17/2022]
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35
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Zhao S, Xie P, Li G, Jun C, Cai Y, Xiong Q, Zhao Y. The proteomic study on cellular responses of the testes of zebrafish (Danio rerio
) exposed to microcystin-RR. Proteomics 2012; 12:300-12. [DOI: 10.1002/pmic.201100214] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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36
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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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37
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Regulation of heat shock protein 27 phosphorylation during microcystin-LR-induced cytoskeletal reorganization in a human liver cell line. Toxicol Lett 2011; 207:270-7. [DOI: 10.1016/j.toxlet.2011.09.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Revised: 09/22/2011] [Accepted: 09/23/2011] [Indexed: 11/24/2022]
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38
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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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39
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Zhang HZ, Zhang FQ, Li CF, Yi D, Fu XL, Cui LX. A Cyanobacterial Toxin, Microcystin-LR, Induces Apoptosis of Sertoli Cells by Changing the Expression Levels of Apoptosis-Related Proteins. TOHOKU J EXP MED 2011; 224:235-42. [DOI: 10.1620/tjem.224.235] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Hui-Zhen Zhang
- Department of Environmental Health, College of Public Health, Zhengzhou University
| | - Feng-Quan Zhang
- Department of Environmental Health, College of Public Health, Zhengzhou University
- Shengzhou Center For Disease Control and Prevention
| | - Chao-Feng Li
- Department of Environmental Health, College of Public Health, Zhengzhou University
| | - Dan Yi
- Department of Environmental Health, College of Public Health, Zhengzhou University
| | - Xiao-Li Fu
- Department of Environmental Health, College of Public Health, Zhengzhou University
| | - Liu-Xin Cui
- Department of Environmental Health, College of Public Health, Zhengzhou University
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40
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Liang W, Chen L, Sui L, Yu J, Wang L, Shi H. Assessment of detoxification of microcystin extracts using electrochemical oxidation. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2011; 46:1102-1112. [PMID: 21806454 DOI: 10.1080/10934529.2011.590721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Microcystins, cyclic heptapeptide toxins produced by cyanobacteria, possess tumor-promoting activity, which act through inhibition of protein phosphatases 1 and 2A. In this study, the variation in toxicity of microcystins from Microcystis aeruginosa during electrooxidation was assessed using bioassays. The microcystin-LR samples (MCLR) were prepared by crude extracts dissolved in electrolytes, e.g., 0.02 mol L(-1) Na(2)SO(4), 0.02 mol L(-1) Na(2)SO(4) containing 0.5 mmol L(-1) NaCl, and tap water. Electrooxidation was conducted at a current density of 4 mA cm(-2) at room temperature (20-26°C), using Ti/RuO(2) anodes. Toxicological profiles for acute toxic effects (Vibrio fischeri) and genotoxic effects (Vicia faba micronucleus assay and single cell gel electrophoresis assay of mice lymphocytes) were determined for both untreated and treated MCLR samples. Results showed that acute toxicity during treatment was caused mainly by residual oxidants from electrooxidation. The by-products from the degradation of MCLR samples showed very weak acute toxicity to V. fischeri. Before electrooxidation, MCLR samples could induce obvious cell damage to V. faba root tips and mice lymphocytes. Electrooxidation degradation significantly decreased the genotoxicity of MCLR samples until the final by-products showed no toxicity. Thus, electrooxidation can detoxify MCLR samples via degradation processes.
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Affiliation(s)
- Wenyan Liang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing, P. R. China.
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41
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Valério E, Chaves S, Tenreiro R. Diversity and impact of prokaryotic toxins on aquatic environments: a review. Toxins (Basel) 2010; 2:2359-410. [PMID: 22069558 PMCID: PMC3153167 DOI: 10.3390/toxins2102359] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 10/01/2010] [Accepted: 10/13/2010] [Indexed: 12/17/2022] Open
Abstract
Microorganisms are ubiquitous in all habitats and are recognized by their metabolic versatility and ability to produce many bioactive compounds, including toxins. Some of the most common toxins present in water are produced by several cyanobacterial species. As a result, their blooms create major threats to animal and human health, tourism, recreation and aquaculture. Quite a few cyanobacterial toxins have been described, including hepatotoxins, neurotoxins, cytotoxins and dermatotoxins. These toxins are secondary metabolites, presenting a vast diversity of structures and variants. Most of cyanobacterial secondary metabolites are peptides or have peptidic substructures and are assumed to be synthesized by non-ribosomal peptide synthesis (NRPS), involving peptide synthetases, or NRPS/PKS, involving peptide synthetases and polyketide synthases hybrid pathways. Besides cyanobacteria, other bacteria associated with aquatic environments are recognized as significant toxin producers, representing important issues in food safety, public health, and human and animal well being. Vibrio species are one of the most representative groups of aquatic toxin producers, commonly associated with seafood-born infections. Some enterotoxins and hemolysins have been identified as fundamental for V. cholerae and V. vulnificus pathogenesis, but there is evidence for the existence of other potential toxins. Campylobacter spp. and Escherichia coli are also water contaminants and are able to produce important toxins after infecting their hosts. Other bacteria associated with aquatic environments are emerging as toxin producers, namely Legionella pneumophila and Aeromonas hydrophila, described as responsible for the synthesis of several exotoxins, enterotoxins and cytotoxins. Furthermore, several Clostridium species can produce potent neurotoxins. Although not considered aquatic microorganisms, they are ubiquitous in the environment and can easily contaminate drinking and irrigation water. Clostridium members are also spore-forming bacteria and can persist in hostile environmental conditions for long periods of time, contributing to their hazard grade. Similarly, Pseudomonas species are widespread in the environment. Since P. aeruginosa is an emergent opportunistic pathogen, its toxins may represent new hazards for humans and animals. This review presents an overview of the diversity of toxins produced by prokaryotic microorganisms associated with aquatic habitats and their impact on environment, life and health of humans and other animals. Moreover, important issues like the availability of these toxins in the environment, contamination sources and pathways, genes involved in their biosynthesis and molecular mechanisms of some representative toxins are also discussed.
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Affiliation(s)
- Elisabete Valério
- Centro de Recursos Microbiológicos (CREM), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal;
| | - Sandra Chaves
- Centro de Biodiversidade, Genómica Integrativa e Funcional (BioFIG), Faculdade de Ciências, Universidade de Lisboa, Edificio ICAT, Campus da FCUL, Campo Grande, 1740-016 Lisboa, Portugal;
| | - Rogério Tenreiro
- Centro de Biodiversidade, Genómica Integrativa e Funcional (BioFIG), Faculdade de Ciências, Universidade de Lisboa, Edificio ICAT, Campus da FCUL, Campo Grande, 1740-016 Lisboa, Portugal;
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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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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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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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Valério E, Chambel L, Paulino S, Faria N, Pereira P, Tenreiro R. Multiplex PCR for detection of microcystins-producing cyanobacteria from freshwater samples. ENVIRONMENTAL TOXICOLOGY 2010; 25:251-260. [PMID: 19489064 DOI: 10.1002/tox.20502] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The aim of this study was to develop a PCR-based method of gene-directed multiplex PCR to rapidly identify microcystins producing cyanobacteria, regardless of their taxa, that could be applied in routine freshwater monitoring. Instead of using the amplification of only one or two mcy gene fragments, a multiplex PCR that simultaneously amplifies mcyA-cd, mcyAB, and mcyB fragments of the microcystin gene cluster was validated with DNA from 124 cyanobacterial isolates and applied in 37 environmental samples. The toxicological status of the isolates was assessed by high-performance liquid chromatography also used as the "gold standard" for the evaluation of multiplex mcy genes-based PCR, where a sensitivity of 92.3% and a specificity of 100% have been obtained. For the environmental samples, a rapid protocol for their direct use in the PCR reaction has been developed and, by using ELISA results as "gold standard" for the presence of microcystins in these samples, a sensitivity of 80% and a specificity of 100% were achieved, showing that this multiplex PCR test is a rapid, reliable, and economical way of assessing the microcystin-producing potential of cyanobacteria in freshwaters, regardless of their taxa or microcystins variant produced.
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Affiliation(s)
- Elisabete Valério
- Faculdade de Ciências, Universidade de Lisboa, Centro de Biodiversidade, Genómica Integrativa e Funcional (BioFIG), Edifício ICAT, Campus da FCUL, Campo Grande, Lisbon, Portugal
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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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Puerto M, Pichardo S, Jos Á, Cameán AM. Microcystin-LR induces toxic effects in differentiated and undifferentiated Caco-2 cells. Arch Toxicol 2010; 84:405-10. [DOI: 10.1007/s00204-010-0513-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 01/14/2010] [Indexed: 11/28/2022]
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Morphological and ultrastructural effects of microcystin-LR from Microcystis aeruginosa extract on a kidney cell line. Toxicon 2009; 54:283-94. [DOI: 10.1016/j.toxicon.2009.04.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 04/13/2009] [Accepted: 04/14/2009] [Indexed: 11/21/2022]
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49
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Malécot M, Mezhoud K, Marie A, Praseuth D, Puiseux-Dao S, Edery M. Proteomic study of the effects of microcystin-LR on organelle and membrane proteins in medaka fish liver. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2009; 94:153-161. [PMID: 19628287 DOI: 10.1016/j.aquatox.2009.06.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 06/16/2009] [Accepted: 06/19/2009] [Indexed: 05/28/2023]
Abstract
The microcystin-leucine-arginine toxin (MC-LR) is produced by cyanobacteria that sometimes bloom in water reservoirs. It targets the liver, thus posing potential health risks to human and animals. Microcystin inhibits the protein phosphatases PP1 and PP2A, leading to diverse cellular deregulation processes. A proteomic approach was applied to the medaka fish (Oryzias latipes) to obtain an overview of the effects of MC-LR on the liver. As membrane and organelle proteins are major structural and functional components of several cell signalling pathways, we decided to investigate here the membrane and organelle-enriched fractions from the livers of control and MC-LR treated medaka fish. Seventeen proteins were identified by proteomic analysis as being modulated in response to MC-LR treatment. This is the first time for eight of them to be reported as being involved in MC-LR effects: prohibitin, fumarylacetoacetase, protein disulfide isomerase A4 and A6, glucose regulated protein 78kDa, 40S ribosomal protein SA, cytochrome b5, and ATP synthase mitochondrial d subunit. These proteins are involved in protein maturation or in the response to oxidative stress highlighting the role of organelles in protein processing and the complex cooperation associated with oxidative stress.
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Affiliation(s)
- Mélodie Malécot
- CNRS, FRE 3206 Molécules de communication et adaptation des microorganismes, and MNHN, USM 505 Cyanobactéries, cyanotoxines et environnement, Département Régulations, développement et diversité moléculaire, Muséum national d'Histoire naturelle, Paris Cedex 05, France
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Comparison of the toxicity induced by microcystin-RR and microcystin-YR in differentiated and undifferentiated Caco-2 cells. Toxicon 2009; 54:161-9. [DOI: 10.1016/j.toxicon.2009.03.030] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 03/27/2009] [Accepted: 03/30/2009] [Indexed: 11/22/2022]
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