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Spencer PS, Valdes Angues R, Palmer VS. Nodding syndrome: A role for environmental biotoxins that dysregulate MECP2 expression? J Neurol Sci 2024; 462:123077. [PMID: 38850769 DOI: 10.1016/j.jns.2024.123077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 05/15/2024] [Accepted: 05/30/2024] [Indexed: 06/10/2024]
Abstract
Nodding syndrome is an epileptic encephalopathy associated with neuroinflammation and tauopathy. This initially pediatric brain disease, which has some clinical overlap with Methyl-CpG-binding protein 2 (MECP2) Duplication Syndrome, has impacted certain impoverished East African communities coincident with local civil conflict and internal displacement, conditions that forced dependence on contaminated food and water. A potential role in Nodding syndrome for certain biotoxins (freshwater cyanotoxins plus/minus mycotoxins) with neuroinflammatory, excitotoxic, tauopathic, and MECP2-dysregulating properties, is considered here for the first time.
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Affiliation(s)
- Peter S Spencer
- Department of Neurology, School of Medicine and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA; Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA; Gulu University School of Medicine, Gulu, Uganda.
| | - Raquel Valdes Angues
- Department of Neurology, School of Medicine and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA
| | - Valerie S Palmer
- Department of Neurology, School of Medicine and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USA; Gulu University School of Medicine, Gulu, Uganda
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2
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Kongsintaweesuk S, Klungsaeng S, Intuyod K, Techasen A, Pairojkul C, Luvira V, Pinlaor S, Pinlaor P. Microcystin-leucine arginine induces the proliferation of cholangiocytes and cholangiocarcinoma cells through the activation of the Wnt/β-catenin signaling pathway. Heliyon 2024; 10:e30104. [PMID: 38720699 PMCID: PMC11076882 DOI: 10.1016/j.heliyon.2024.e30104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 04/19/2024] [Accepted: 04/19/2024] [Indexed: 05/12/2024] Open
Abstract
Background Microcystin-leucine arginine (MC-LR) is a cyanobacterial hepatotoxic toxin found in water sources worldwide, including in northeastern Thailand, where opisthorchiasis-associated cholangiocarcinoma (CCA) is most prevalent. MC-LR is a potential carcinogen; however, its involvement in liver fluke-associated CCA remains ambiguous. Here, we aimed to evaluate the effect of MC-LR on the progression of CCA via the Wnt/β-catenin pathway in vitro. Methods Cell division, migration, cell cycle transition, and MC-LR transporter expression were evaluated in vitro through MTT assay, wound healing assay, flow cytometry, and immunofluorescence staining, respectively. Following a 24-h treatment of cultured cells with 1, 10, 100, and 1,000 nM of MC-LR, the proliferative effect of MC-LR on the Wnt/β-catenin signaling pathway was investigated using immunoblotting and qRT-PCR analysis. Immunohistochemistry was used to determine β-catenin expression in CCA tissue compared to adjacent tissue. Results Human immortalized cholangiocyte cells (MMNK-1) and a human cell line established from opisthorchiasis-associated CCA (KKU-213B) expressed the MC-LR transporter and internalized MC-LR. Exposure to 10 nM and 100 nM of MC-LR notably enhanced cells division and migration in both cell lines (P < 0.05) and markedly elevated the percentage of S phase cells (P < 0.05). MC-LR elevated PP2A expression by activating the Wnt/β-catenin signaling pathway and suppressing phosphatase activity. Inhibition of the β-catenin destruction complex genes (Axin1 and APC) led to the upregulation of β-catenin and its downstream target genes (Cyclin D1 and c-Jun). Inhibition of Wnt/β-catenin signaling by MSAB confirmed these results. Additionally, β-catenin was significantly expressed in cancerous tissue compared to adjacent areas (P < 0.001). Conclusions Our findings suggest that MC-LR promotes cell proliferation and progression of CCA through Wnt/β-catenin pathway. Further evaluation using invivo experiments is needed to confirm this observation. This finding could promote health awareness regarding MC-LR intake and risk of CCA.
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Affiliation(s)
- Suppakrit Kongsintaweesuk
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
- Medical Sciences Program, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Sirinapha Klungsaeng
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Kitti Intuyod
- Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Anchalee Techasen
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
- School of Medical Technology, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Chawalit Pairojkul
- Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Vor Luvira
- Department of Surgery, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Somchai Pinlaor
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Porntip Pinlaor
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
- School of Medical Technology, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen 40002, Thailand
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Kashani E, Vassella E. Pleiotropy of PP2A Phosphatases in Cancer with a Focus on Glioblastoma IDH Wildtype. Cancers (Basel) 2022; 14:5227. [PMID: 36358647 PMCID: PMC9654311 DOI: 10.3390/cancers14215227] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 07/29/2023] Open
Abstract
Serine/Threonine protein phosphatase 2A (PP2A) is a heterotrimeric (or occasionally, heterodimeric) phosphatase with pleiotropic functions and ubiquitous expression. Despite the fact that they all contribute to protein dephosphorylation, multiple PP2A complexes exist which differ considerably by their subcellular localization and their substrate specificity, suggesting diverse PP2A functions. PP2A complex formation is tightly regulated by means of gene expression regulation by transcription factors, microRNAs, and post-translational modifications. Furthermore, a constant competition between PP2A regulatory subunits is taking place dynamically and depending on the spatiotemporal circumstance; many of the integral subunits can outcompete the rest, subjecting them to proteolysis. PP2A modulation is especially important in the context of brain tumors due to its ability to modulate distinct glioma-promoting signal transduction pathways, such as PI3K/Akt, Wnt, Ras, NF-κb, etc. Furthermore, PP2A is also implicated in DNA repair and survival pathways that are activated upon treatment of glioma cells with chemo-radiation. Depending on the cancer cell type, preclinical studies have shown some promise in utilising PP2A activator or PP2A inhibitors to overcome therapy resistance. This review has a special focus on "glioblastoma, IDH wild-type" (GBM) tumors, for which the therapy options have limited efficacy, and tumor relapse is inevitable.
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Affiliation(s)
- Elham Kashani
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Erik Vassella
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
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Lin W, Hung TC, Kurobe T, Wang Y, Yang P. Microcystin-Induced Immunotoxicity in Fishes: A Scoping Review. Toxins (Basel) 2021; 13:765. [PMID: 34822549 PMCID: PMC8623247 DOI: 10.3390/toxins13110765] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 12/26/2022] Open
Abstract
Cyanobacteria (blue-green algae) have been present on Earth for over 2 billion years, and can produce a variety of bioactive molecules, such as cyanotoxins. Microcystins (MCs), the most frequently detected cyanotoxins, pose a threat to the aquatic environment and to human health. The classic toxic mechanism of MCs is the inhibition of the protein phosphatases 1 and 2A (PP1 and PP2A). Immunity is known as one of the most important physiological functions in the neuroendocrine-immune network to prevent infections and maintain internal homoeostasis in fish. The present review aimed to summarize existing papers, elaborate on the MC-induced immunotoxicity in fish, and put forward some suggestions for future research. The immunomodulatory effects of MCs in fish depend on the exposure concentrations, doses, time, and routes of exposure. Previous field and laboratory studies provided strong evidence of the associations between MC-induced immunotoxicity and fish death. In our review, we summarized that the immunotoxicity of MCs is primarily characterized by the inhibition of PP1 and PP2A, oxidative stress, immune cell damage, and inflammation, as well as apoptosis. The advances in fish immunoreaction upon encountering MCs will benefit the monitoring and prediction of fish health, helping to achieve an ecotoxicological goal and to ensure the sustainability of species. Future studies concerning MC-induced immunotoxicity should focus on adaptive immunity, the hormesis phenomenon and the synergistic effects of aquatic microbial pathogens.
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Affiliation(s)
- Wang Lin
- Hunan Provincial Collaborative Innovation Center for Efficient and Health Production of Fisheries, Hunan Provincial Key Laboratory for Health Aquaculture and Product Processing in Dongting Lake Area, Hunan Provincial Key Laboratory for Molecular Immunity Technology of Aquatic Animal Diseases, Hunan Engineering Research Center of Aquatic Organism Resources and Environmental Ecology, Zoology Key Laboratory of Hunan Higher Education, College of Life and Environmental Sciences, Hunan University of Arts and Science, Changde 415000, China;
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA; (T.-C.H.); (Y.W.)
- Department of Fisheries Resources and Environment, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Tien-Chieh Hung
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA; (T.-C.H.); (Y.W.)
| | - Tomofumi Kurobe
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, CA 95616, USA;
| | - Yi Wang
- Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, USA; (T.-C.H.); (Y.W.)
| | - Pinhong Yang
- Hunan Provincial Collaborative Innovation Center for Efficient and Health Production of Fisheries, Hunan Provincial Key Laboratory for Health Aquaculture and Product Processing in Dongting Lake Area, Hunan Provincial Key Laboratory for Molecular Immunity Technology of Aquatic Animal Diseases, Hunan Engineering Research Center of Aquatic Organism Resources and Environmental Ecology, Zoology Key Laboratory of Hunan Higher Education, College of Life and Environmental Sciences, Hunan University of Arts and Science, Changde 415000, China;
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Lynch KD, Montonye ML, Tian DD, Arman T, Oyanna VO, Bechtold BJ, Graf TN, Oberlies NH, Paine MF, Clarke JD. Hepatic organic anion transporting polypeptides mediate disposition of milk thistle flavonolignans and pharmacokinetic silymarin-drug interactions. Phytother Res 2021; 35:3286-3297. [PMID: 33587330 PMCID: PMC8217340 DOI: 10.1002/ptr.7049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/23/2020] [Accepted: 01/21/2021] [Indexed: 01/17/2023]
Abstract
Silybum marianum (L.) Gaertn. (Asteraceae), commonly known as milk thistle, is a botanical natural product used to self-treat multiple diseases such as Type 2 diabetes mellitus and nonalcoholic steatohepatitis (NASH). An extract from milk thistle seeds (achenes), termed silymarin, is comprised primarily of several flavonolignans. Systemic concentrations of these flavonolignans can influence the potential biologic effects of silymarin and the risk for pharmacokinetic silymarin-drug interactions. The aims of this research were to determine the roles of organic anion transporting polypeptides (OATPs/Oatps) in silymarin flavonolignan disposition and in pharmacokinetic silymarin-drug interactions. The seven major flavonolignans from silymarin were determined to be substrates for OATP1B1, OATP1B3, and OATP2B1. Sprague Dawley rats were fed either a control diet or a NASH-inducing diet and administered pitavastatin (OATP/Oatp probe substrate), followed by silymarin via oral gavage. Decreased protein expression of Oatp1b2 and Oatp1a4 in NASH animals increased flavonolignan area under the plasma concentration-time curve (AUC) and maximum plasma concentration. The combination of silymarin inhibition of Oatps and NASH-associated decrease in Oatp expression caused an additive increase in plasma pitavastatin AUC in the animals. These data indicate that OATPs/Oatps contribute to flavonolignan cellular uptake and mediate the interaction between silymarin and NASH on pitavastatin systemic exposure.
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Affiliation(s)
- Katherine D. Lynch
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Michelle L. Montonye
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Dan-Dan Tian
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Tarana Arman
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Victoria O. Oyanna
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Baron J. Bechtold
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Tyler N. Graf
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina
| | - Nicholas H. Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina
| | - Mary F. Paine
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - John D. Clarke
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
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Arman T, Lynch KD, Goedken M, Clarke JD. Sub-chronic microcystin-LR renal toxicity in rats fed a high fat/high cholesterol diet. CHEMOSPHERE 2021; 269:128773. [PMID: 33143886 PMCID: PMC8276626 DOI: 10.1016/j.chemosphere.2020.128773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/24/2020] [Accepted: 10/25/2020] [Indexed: 05/16/2023]
Abstract
Microcystin-LR (MCLR) is a liver and kidney toxin produced by cyanobacteria. Recently, it was demonstrated that MCLR exposure drives the progression of high fat/high cholesterol (HFHC) induced nonalcoholic fatty liver disease (NAFLD) to a more severe state. NAFLD is also a risk factor for chronic kidney disease (CKD), and the current study investigated MCLR renal toxicity in the context of an HFHC diet. Sprague Dawley rats were fed either a control diet or an HFHC diet for 10 weeks. After 6 weeks of diet, animals were administered either vehicle, 10 μg/kg, or 30 μg/kg MCLR via intraperitoneal injection every other day for 4 weeks. HFHC diet alone increased the renal glomerular change histopathology score, and 30 μg/kg MCLR exposure increased this score in both the control group and the HFHC group. In contrast, 30 μg/kg MCLR caused greater proteinuria and cast formation and decreased protein phosphatase 1 and 2A protein expression in the HFHC group. Urinary excretion of KIM-1 increased, but albumin and tamm-horsfall protein did not change after MCLR exposure. The general concordance between KIM-1, polyuria, proteinuria, and renal casts after MCLR exposure suggests that proximal tubule cell damage contributed to these connected pathologies. The control group adapted to repeated MCLR exposure by increasing the urinary elimination of MCLR and its metabolites, whereas this adaptation was blunted in the HFHC group. These data suggest an HFHC diet may increase the severity of certain MCLR-elicited renal toxicities.
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Affiliation(s)
- Tarana Arman
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, 99202, USA
| | - Katherine D Lynch
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, 99202, USA
| | - Michael Goedken
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ, 08901, USA
| | - John D Clarke
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, 99202, USA.
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Impacts of Microcystins on Morphological and Physiological Parameters of Agricultural Plants: A Review. PLANTS 2021; 10:plants10040639. [PMID: 33800599 PMCID: PMC8065763 DOI: 10.3390/plants10040639] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 11/17/2022]
Abstract
Cyanobacteria are a group of photosynthetic prokaryotes that pose a great concern in the aquatic environments related to contamination and poisoning of wild life and humans. Some species of cyanobacteria produce potent toxins such as microcystins (MCs), which are extremely aggressive to several organisms, including animals and humans. In order to protect human health and prevent human exposure to this type of organisms and toxins, regulatory limits for MCs in drinking water have been established in most countries. In this regard, the World Health Organization (WHO) proposed 1 µg MCs/L as the highest acceptable concentration in drinking water. However, regulatory limits were not defined in waters used in other applications/activities, constituting a potential threat to the environment and to human health. Indeed, water contaminated with MCs or other cyanotoxins is recurrently used in agriculture and for crop and food production. Several deleterious effects of MCs including a decrease in growth, tissue necrosis, inhibition of photosynthesis and metabolic changes have been reported in plants leading to the impairment of crop productivity and economic loss. Studies have also revealed significant accumulation of MCs in edible tissues and plant organs, which raise concerns related to food safety. This work aims to systematize and analyze the information generated by previous scientific studies, namely on the phytotoxicity and the impact of MCs especially on growth, photosynthesis and productivity of agricultural plants. Morphological and physiological parameters of agronomic interest are overviewed in detail in this work, with the aim to evaluate the putative impact of MCs under field conditions. Finally, concentration-dependent effects are highlighted, as these can assist in future guidelines for irrigation waters and establish regulatory limits for MCs.
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Xiao C, Mei F, Ren G, Long L, Chen M, Fang X, Li J, Li K, Tang Y, Huang T, Deng W. Synergistic Effect of MC-LR and C-Terminal Truncated HBx on HepG2 Cells and Their Effects on PP2A Mediated Downstream Target of MAPK Signaling Pathway. Front Genet 2020; 11:537785. [PMID: 33193609 PMCID: PMC7593820 DOI: 10.3389/fgene.2020.537785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 09/28/2020] [Indexed: 12/24/2022] Open
Abstract
C-terminally truncated hepatitis B virus (HBV) X (ctHBx) infection and exposure to microcystins-LR (MC-LR) can lead to human hepatitis and liver cancer, but the mechanism associated with their synergistically effects not been fully elucidated. The ctHBx (HBxΔ4 and HBxΔ32) lentivirus were constructed and transfected into the HepG2 cells. Then we investigated the function of MC-LR and ctHBx using the molecular biology approaches, including enzyme-linked immunosorbent assay, clone formation assay, scratch wound testing, transwell assays, carried out flow cytometry respectively to examine cell cycle and apoptosis in each group, and detected the related proteins of HBx, MEK/ERK/JNK/p38 in mitogen-activated protein kinase (MAPK) pathway and the downstream proteins such as cdc2, cdc25C, and p53 by western blotting. We found that the protein phosphorylase 2A (PP2A) enzyme activity in MC-LR and HBxΔ32/HBxΔ4 groups decreased more than in MC-LR and HBx group at the same time point and MC-LR concentration (P < 0.05). Meanwhile the proliferation, migration, invasion and colony formation capability of HepG2 cells were significantly enhanced in MC-LR and ctHBx groups (P < 0.05). In addition the proportion of S stage cells in the MC-LR-treated HBxΔ32/HBxΔ4 groups was significantly greater than that in the untreated groups (P < 0.05). Furthermore, the protein expression of MAPK signaling pathway including phospho-MEK1/2, ERKl/2, p38, and JNK were up-regulated by MC-LR and HBxΔ32, and the expression of cyclin-related proteins, including p53, cdc25C, and cdc2 were also activated (P < 0.05). Taken together, our findings revealed the essential significance of the MC-LR and ctHBx on the PP2A/MAPK/p53, cdc25C and cdc2 axis in the formation and development of HCC and identified MC-LR and ctHBx as potential causal cofactors of hepatocarcinogenesis.
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Affiliation(s)
- Chanchan Xiao
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Fanbiao Mei
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Guanhua Ren
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Long Long
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Maojian Chen
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Xiang Fang
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Jilin Li
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Kezhi Li
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Yanping Tang
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Tianren Huang
- Guangxi Medical University Cancer Hospital, Nanning, China
| | - Wei Deng
- Guangxi Medical University Cancer Hospital, Nanning, China
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Llana-Ruiz-Cabello M, Jos A, Cameán A, Oliveira F, Barreiro A, Machado J, Azevedo J, Pinto E, Almeida A, Campos A, Vasconcelos V, Freitas M. Analysis of the Use of Cylindrospermopsin and/or Microcystin-Contaminated Water in the Growth, Mineral Content, and Contamination of Spinacia oleracea and Lactuca sativa. Toxins (Basel) 2019; 11:E624. [PMID: 31661886 PMCID: PMC6891636 DOI: 10.3390/toxins11110624] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/20/2019] [Accepted: 10/25/2019] [Indexed: 01/08/2023] Open
Abstract
Cyanobacteria and cyanotoxins constitute a serious environmental and human health problem. Moreover, concerns are raised with the use of contaminated water in agriculture and vegetable production as this can lead to food contamination and human exposure to toxins as well as impairment in crop development and productivity. The objective of this work was to assess the susceptibility of two green vegetables, spinach and lettuce, to the cyanotoxins microcystin (MC) and cylindrospermopsin (CYN), individually and in mixture. The study consisted of growing both vegetables in hydroponics, under controlled conditions, for 21 days in nutrient medium doped with MC or CYN at 10 μg/L and 50 μg/L, or CYN/MC mixture at 5 + 5 μg/L and 25 + 25 μg/L. Extracts from M. aeruginosa and C. ovalisporum were used as sources of toxins. The study revealed growth inhibition of the aerial part (Leaves) in both species when treated with 50µg/L of MC, CYN and CYN/MC mixture. MC showed to be more harmful to plant growth than CYN. Moreover spinach leaves growth was inhibited by both 5 + 5 and 25 + 25 µg/L CYN/MC mixtures, whereas lettuce leaves growth was inhibited only by 25 + 25 µg/L CYN/MC mixture. Overall, growth data evidence increased sensitivity of spinach to cyanotoxins in comparison to lettuce. On the other hand, plants exposed to CYN/MC mixture showed differential accumulation of CYN and MC. In addition, CYN, but not MC, was translocated from the roots to the leaves. CYN and MC affected the levels of minerals particularly in plant roots. The elements most affected were Ca, K and Mg. However, in leaves K was the mineral that was affected by exposure to cyanotoxins.
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Affiliation(s)
- Maria Llana-Ruiz-Cabello
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, Profesor García González n°2, 41012 Seville, Spain.
| | - Angeles Jos
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, Profesor García González n°2, 41012 Seville, Spain.
| | - Ana Cameán
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, Profesor García González n°2, 41012 Seville, Spain.
| | - Flavio Oliveira
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.
| | - Aldo Barreiro
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.
| | - Joana Machado
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.
| | - Joana Azevedo
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.
| | - Edgar Pinto
- LAQV/REQUIMTE, Departament of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal.
- Polytechnic Institute of Porto, Department of Environmental Health, School of Health, CISA/Research Center in Environment and Health, Rua Dr. António Bernardino de Almeida, 400, 4200-072 Porto, Portugal.
| | - Agostinho Almeida
- LAQV/REQUIMTE, Departament of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal.
| | - Alexandre Campos
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.
| | - Vitor Vasconcelos
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.
- Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal.
| | - Marisa Freitas
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal.
- Polytechnic Institute of Porto, Department of Environmental Health, School of Health, CISA/Research Center in Environment and Health, Rua Dr. António Bernardino de Almeida, 400, 4200-072 Porto, Portugal.
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Moreira DA, Soares RM, Valente RH, Bebianno MJ, Rebelo MF. Molecular effects of Microcystin-LA in tilapia (Oreochromis niloticus). Toxicon 2019; 166:76-82. [PMID: 31121173 DOI: 10.1016/j.toxicon.2019.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 04/25/2019] [Accepted: 05/11/2019] [Indexed: 10/26/2022]
Abstract
Nile tilapia (Oreochromis niloticus) is a freshwater phytoplanktivorous fish species reported to accumulate and tolerate large amounts of cyanotoxins such as microcystins (MCs). The present study aimed to investigate molecular responses to the acute exposure of Nile tilapia to the Microcystin-LA analogue (MC-LA). Thus, the specimens were sublethally exposed to 1000 μg kg-1 of MC-LA for 12, 24, 48, and 96 h. Gene expression of PP1, PP2A, GST, GPX and actin was analyzed by quantitative PCR. The protein abundance profile of PP2A was determined by immunoblotting, while the integrity of its biological function was assessed by a phosphatase enzymatic assay. PP2A activity was significantly and strongly reduced by MC-LA. A resulting feedback mechanism significantly increased PP2A gene expression and protein abundance in all assessed times. However, a recovery of that phosphatase activity was not observed. In this study, the observed increase in GPX gene expression was the only response that could be directly related to the unknown factors associated to the fish survival to such high dose exposure.
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Affiliation(s)
- Daniel A Moreira
- Laboratory of Environmental Molecular Biology, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Graduate Program in Computational and Systems Biology, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Raquel M Soares
- Multidisciplinary Center of Research in Biology - NUMPEX-BIO - Campus Duque de Caxias, Universidade Federal do Rio de Janeiro, Duque de Caxias, RJ, Brazil.
| | - Richard H Valente
- Laboratory of Toxinology, Instituto Oswaldo Cruz. Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Maria J Bebianno
- Laboratory of Environmental Molecular Biology, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; CIMA, University of Algarve, Campus de Gambelas, 8000-397, Faro, Portugal
| | - Mauro F Rebelo
- Laboratory of Environmental Molecular Biology, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Sopezki MDS, Monserrat JM, Yunes JS, Zanette J. Validation of Housekeeping Genes as Internal Controls for the Study of the Effects of Microcystin-LR in Zebrafish by Real-Time PCR. Zebrafish 2018; 15:454-459. [PMID: 30044200 DOI: 10.1089/zeb.2018.1598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Microcystin-leucine arginine (MC-LR) is a natural toxin produced by cyanobacterial blooms that causes severe liver damage in fish. It is crucial to investigate if housekeeping genes are affected by MC-LR in zebrafish, to permit the adequate evaluation of gene expression by RT-qPCR. We evaluated the gene expression stability (M value) and regulation by chemical treatment (using E-Ct and E-ΔCt) to validate the use of eight housekeeping genes in fish exposed to 0, 0.31, and 6.10 μg L-1 MC-LR for 24 h. We suggest the use of the combination of β-actin1, b2m, and arnt2 in the liver and β-actin1, 18S rRNA, and arnt2 in gills as housekeeping genes. The evaluation of gene regulation following MC-LR exposure denoted a strong repression of 18S rRNA (17- and 10-fold decrease) and tbp (10- and 2-fold decrease) and induction of ef-1α (8- and 14-fold increase) in the liver of zebrafish exposed to 0.31 and 6.10 μg L-1 MC-LR, respectively. This is the first study showing that housekeeping genes commonly used in gene expression could be affected in the liver by environmentally relevant concentrations of MC-LR. The study validates adequate housekeeping genes that could be used in toxicological studies with MC-LR in zebrafish.
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Affiliation(s)
- Mauricio da Silva Sopezki
- 1 Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande , Rio Grande, Brazil
| | - José Maria Monserrat
- 1 Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande , Rio Grande, Brazil
| | - João Sarkis Yunes
- 2 Laboratório de Cianobactérias e Ficotoxinas, Instituto de Oceanografia, Universidade Federal do Rio Grande , Rio Grande, Brazil
| | - Juliano Zanette
- 1 Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande , Rio Grande, Brazil
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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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Douglas GC, Thirkill TL, Kumar P, Loi M, Hilborn ED. Effect of microcystin-LR on human placental villous trophoblast differentiation in vitro. ENVIRONMENTAL TOXICOLOGY 2016; 31:427-439. [PMID: 25346179 DOI: 10.1002/tox.22056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 09/19/2014] [Accepted: 10/01/2014] [Indexed: 06/04/2023]
Abstract
Microcystin-LR is a cyanobacterial toxin found in surface and recreational waters that inhibits protein phosphatases and may disrupt the cytoskeleton. Microcystins induce apoptosis in hepatocytes at ≤ 2.0 µM. Nothing is known about the effects of microcystins on human placental trophoblast differentiation and function. The differentiation of villous trophoblasts to form syncytiotrophoblast occurs throughout pregnancy and is essential for normal placental and fetal development. To investigate the effects of microcystin, villous cytotrophoblasts were isolated from term placentas using an established method and exposed to microcystin-LR. Microcystin-LR below the cytotoxic dose of 25 µM did not cause cell rounding or detachment, had no effect on apoptosis, and no effect on the morphological differentiation of mononucleated cytotrophoblasts to multinucleated syncytiotrophoblast. However, secretion of human chorionic gonadotropin (hCG) increased in a microcystin-LR dose-dependent manner. When incubated with l-buthionine sulphoximine (BSO) to deplete glutathione levels, trophoblast morphological differentiation proceeded normally in the presence of microcystin-LR. Microcystin-LR did not disrupt the trophoblast microtubule cytoskeleton, which is known to play a role in trophoblast differentiation. Immunofluorescence studies showed that trophoblasts express organic anion transport protein 1B3 (OATP1B3), a known microcystin transport protein. In comparison to hepatocytes, trophoblasts appear to be more resistant to the toxic effects of microcystin-LR. The physiological implications of increased hCG secretion in response to microcystin-LR exposure remain to be determined.
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Affiliation(s)
- Gordon C Douglas
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, USA
| | - Twanda L Thirkill
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, USA
| | - Priyadarsini Kumar
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, USA
| | - Minerva Loi
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California Davis, Davis, California, USA
| | - Elizabeth D Hilborn
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, North Carolina, USA
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Chen L, Chen J, Zhang X, Xie P. A review of reproductive toxicity of microcystins. JOURNAL OF HAZARDOUS MATERIALS 2016; 301:381-99. [PMID: 26521084 DOI: 10.1016/j.jhazmat.2015.08.041] [Citation(s) in RCA: 233] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 08/20/2015] [Accepted: 08/23/2015] [Indexed: 05/25/2023]
Abstract
Animal studies provide strong evidence of positive associations between microcystins (MCs) exposure and reproductive toxicity, representing a threat to human reproductive health and the biodiversity of wild life. This paper reviews current knowledge of the reproductive toxicity of MCs, with regard to mammals, fishes, amphibians, and birds, mostly in males. Toxicity of MCs is primarily governed by the inhibition of protein phosphatases 1 and 2A (PP1 and PP2A) and disturbance of cellular phosphorylation balance. MCs exposure is related to excessive production of reactive oxygen species (ROS) and oxidative stress, leading to cytoskeleton disruption, mitochondria dysfunction, endoplasmic reticulum (ER) stress, and DNA damage. MCs induce cell apoptosis mediated by the mitochondrial and ROS and ER pathways. Through PP1/2A inhibition and oxidative stress, MCs lead to differential expression/activity of transcriptional factors and proteins involved in the pathways of cellular differentiation, proliferation, and tumor promotion. MC-induced DNA damage is also involved in carcinogenicity. Apart from a direct effect on testes and ovaries, MCs indirectly affect sex hormones by damaging the hypothalamic-pituitary-gonad (HPG) axis and liver. Parental exposure to MCs may result in hepatotoxicity and neurotoxicity of offspring. We also summarize the current research gaps which should be addressed by further studies.
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Affiliation(s)
- Liang Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Jun Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Xuezhen Zhang
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China.
| | - Ping Xie
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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15
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Liu J, Wang H, Wang B, Chen T, Wang X, Huang P, Xu L, Guo Z. Microcystin-LR promotes proliferation by activating Akt/S6K1 pathway and disordering apoptosis and cell cycle associated proteins phosphorylation in HL7702 cells. Toxicol Lett 2016; 240:214-25. [DOI: 10.1016/j.toxlet.2015.10.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/30/2015] [Accepted: 10/17/2015] [Indexed: 12/14/2022]
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16
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Adamovsky O, Moosova Z, Pekarova M, Basu A, Babica P, Svihalkova Sindlerova L, Kubala L, Blaha L. Immunomodulatory Potency of Microcystin, an Important Water-Polluting Cyanobacterial Toxin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:12457-12464. [PMID: 26380879 DOI: 10.1021/acs.est.5b02049] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Microcystins (MCs) are primarily hepatotoxins produced by cyanobacteria and are responsible for intoxication in humans and animals. There are many incidents of chronic exposure to MCs, which have been attributed to the inappropriate treatment of water supplies or contaminated food. Using RAW 264.7 macrophages, we showed the potency of microcystin-LR (MC-LR) to stimulate production of pro-inflammatory cytokines (tumor necrosis factor α and interleukin-6) as a consequence of fast nuclear factor κB and nitrogen-activated protein kinase activation. In contrast to other studies, the observed effects were not attributed to the intracellular inhibition of protein phosphatases 1/2A due to lack of specific transmembrane transporters for MCs. However, the MC-LR-induced activation of macrophages was effectively inhibited by a specific peptide that blocks signaling of receptors, which play a pivotal role in the innate immune responses. Taken together, we showed for the first time that MC-LR could interfere with macrophage receptors that are responsible for triggering the above-mentioned signaling pathways. These findings provide an interesting mechanistic explanation of some adverse health outcomes associated with toxic cyanobacteria and MCs.
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Affiliation(s)
- Ondrej Adamovsky
- Faculty of Science, RECETOX, Masaryk University , Kamenice 753/5, 62500 Brno, Czech Republic
| | - Zdena Moosova
- Faculty of Science, RECETOX, Masaryk University , Kamenice 753/5, 62500 Brno, Czech Republic
| | - Michaela Pekarova
- Institute of Biophysics, Academy of Sciences , Královopolská 135, 612 65 Brno, Czech Republic
| | - Amrita Basu
- Faculty of Science, RECETOX, Masaryk University , Kamenice 753/5, 62500 Brno, Czech Republic
| | - Pavel Babica
- Faculty of Science, RECETOX, Masaryk University , Kamenice 753/5, 62500 Brno, Czech Republic
| | | | - Lukas Kubala
- Institute of Biophysics, Academy of Sciences , Královopolská 135, 612 65 Brno, Czech Republic
| | - Ludek Blaha
- Faculty of Science, RECETOX, Masaryk University , Kamenice 753/5, 62500 Brno, Czech Republic
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Lin KY, Kao SH, Lai CM, Chen CT, Wu CY, Hsu HJ, Wang WD. Tumor Suppressor Lzap Suppresses Wnt/β-Catenin Signaling to Promote Zebrafish Embryonic Ventral Cell Fates via the Suppression of Inhibitory Phosphorylation of Glycogen Synthase Kinase 3. J Biol Chem 2015; 290:29808-19. [PMID: 26475862 DOI: 10.1074/jbc.m115.669309] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Indexed: 11/06/2022] Open
Abstract
Wnt/β-catenin signaling controls various cell fates in metazoan development, and its dysregulation is often associated with cancer formation. However, regulations of this signaling pathway are not completely understood. Here, we report that Lzap, a tumor suppressor, controls nuclear translocation of β-catenin. In zebrafish embryos disruption of lzap increases the expression of chordin (chd), which encodes a bone morphogenetic protein (BMP) antagonist that is localized in prospective dorsal cells and promotes dorsal fates. Consistently, lzap-deficient embryos with attenuated BMP signaling are dorsalized, which can be rescued by overexpression of zebrafish lzap or bmp2b or human LZAP. The expansion of chd expression in embryos lacking lzap is due to the accumulation of nuclear β-catenin in ventral cells, in which β-catenin is usually degraded. Furthermore, the activity of GSK3, a master regulator of β-catenin degradation, is suppressed in lzap-deficient embryos via inhibitory phosphorylation. Finally, we also report that a similar regulatory axis is also likely to be present in a human tongue carcinoma cell line, SAS. Our results reveal that Lzap is a novel regulator of GSK3 for the maintenance of ventral cell properties and may prevent carcinogenesis via the regulation of β-catenin degradation.
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Affiliation(s)
- Kun-Yang Lin
- From the Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan, Department of BioAgricultural Science, National Chiayi University, Chiayi 60004, Taiwan, and
| | - Shih-Han Kao
- From the Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Chun-Ming Lai
- From the Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan, Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung-Hsing University and Academia Sinica, Taipei 11529, Taiwan
| | - Ciao-Ting Chen
- Department of BioAgricultural Science, National Chiayi University, Chiayi 60004, Taiwan, and
| | - Chang-Yi Wu
- Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung City 80424, Taiwan
| | - Hwei-Jan Hsu
- From the Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan,
| | - Wen-Der Wang
- Department of BioAgricultural Science, National Chiayi University, Chiayi 60004, Taiwan, and
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Huang X, Chen L, Liu W, Qiao Q, Wu K, Wen J, Huang C, Tang R, Zhang X. Involvement of oxidative stress and cytoskeletal disruption in microcystin-induced apoptosis in CIK cells. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 165:41-50. [PMID: 26022555 DOI: 10.1016/j.aquatox.2015.05.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 05/08/2015] [Accepted: 05/10/2015] [Indexed: 06/04/2023]
Abstract
The outbreak of cyanobacterial blooms induces the production and release of microcystins (MCs) into water, representing a health hazard to aquatic organisms and even humans. Some recent studies have suggested that kidney is another important target organ of MCs except liver, however, the potential toxicity mechanisms are still unclear. In this study, we first investigated the collaborative effect of oxidative stress and cytoskeletal disruption in microcystin-induced apoptosis in CIK (Ctenopharyngodon idellus kidney) cells in vitro. CIK cells were treated with 0, 1, 10, and 100μg/L microcystin-LR (MC-LR) for 24 and 48h. Cell viability was increased by MC-LR in 1μg/L group, while decreased in 100μg/L group at 48h. Cell cycle assay showed that 1 and 10μg/L MC-LR induced cell cycle through G1 into S and G2/M phases, while 100μg/L MC-LR reduced G2/M phase population. MC-LR markedly induced apoptosis in 10 and 100μg/L groups. Elevated reactive oxygen species (ROS) production, increased malondialdehyde (MDA) contents, decreased glutathione (GSH) levels, and modulated antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) were observed in CIK cells exposed to MC-LR. These alterations were more pronounced at higher doses (10 and 100μg/L), indicating that oxidative stress was induced by MC-LR. Laser scanning confocal microscope observation showed aggregation and collapse of microfilaments (MFs) and microtubules (MTs) in CIK cells, and even loss of some cytoskeleton structure. Moreover, transcriptional changes of cytoskeletal genes (β-actin, lc3a, and keratin) were also determined, which have a high probability with cytoskeleton structure damage. Our data suggest that oxidative stress and cytoskeletal disruption may interact with each other and jointly lead to apoptosis and renal toxicity induced by MCs.
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Affiliation(s)
- Xiao Huang
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
| | - Liang Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wanjing Liu
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
| | - Qin Qiao
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
| | - Kang Wu
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
| | - Jing Wen
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
| | - Cuihong Huang
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
| | - Rong Tang
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
| | - Xuezhen Zhang
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China.
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Meng G, Liu J, Lin S, Guo Z, Xu L. Microcystin-LR-caused ROS generation involved in p38 activation and tau hyperphosphorylation in neuroendocrine (PC12) cells. ENVIRONMENTAL TOXICOLOGY 2015; 30:366-374. [PMID: 24142891 DOI: 10.1002/tox.21914] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/23/2013] [Accepted: 10/02/2013] [Indexed: 06/02/2023]
Abstract
Microcystin-LR (MC-LR), a potent specific hepatotoxin produced by cyanobacteria, has recently been reported to show neurotoxicity. Our previous study demonstrated that MC-LR caused the reorganization of cytoskeleton architectures and hyperphosphorylation of the cytoskeletal-associated proteins tau and HSP27 in neuroendocrine PC12 cell line by direct PP2A inhibition and indirect p38 mitogen-activated protein kinase (MAPK) activation. It has been shown that oxidative stress is extensively associated with MC-LR toxicity, mainly resulting from an excessive production of reactive oxygen species (ROS). However, the mechanisms by which ROS mediates the cytotoxic action of MC-LR are unclear. In the present study, we investigated whether ROS might play a critical role in MC-LR-induced hyperphosphorylation of microtubule-associated protein tau and the activation of the MAPKs in PC12 cell line. The results showed that MC-LR had time- and concentration-dependent effects on ROS generation, p38-MAPK activation and tau phosphorylation. The time-course studies indicated similar biphasic changes in ROS generation and tau hyperphosphorylation, which started to increase within 1 h and reached the maximum level at 3 h followed by a decrease after prolonged treatment. Furthermore, pretreatment with the antioxidants, N-acetylcysteine and vitamin C, significantly decreased MC-LR-induced ROS generation and effectively attenuated p38-MAPK activation as well as tau hyperphosphorylation. Taken together, these findings suggest that ROS generation triggered by MC-LR is a key intracellular event that contributes to an induction of p38-MAPK activation and tau phosphorylation, and that blockade of this ROS-mediated redox-sensitive signal cascades may attenuate the toxic effects of MC-LR.
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Affiliation(s)
- Guanmin Meng
- Department of Clinical Laboratory, Tongde Hospital of Zhejiang Province, 234 Gucui Road, Hangzhou, 310012, China; Department of Biochemistry, School of Medicine, Zhejiang University, 866th Yu Hang Tang Road, Hangzhou, 310058, China
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20
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Wang H, Liu J, Lin S, Wang B, Xing M, Guo Z, Xu L. MCLR-induced PP2A inhibition and subsequent Rac1 inactivation and hyperphosphorylation of cytoskeleton-associated proteins are involved in cytoskeleton rearrangement in SMMC-7721 human liver cancer cell line. CHEMOSPHERE 2014; 112:141-153. [PMID: 25048900 DOI: 10.1016/j.chemosphere.2014.03.130] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 06/03/2023]
Abstract
Cyanobacteria-derived toxin microcystin-LR (MCLR) has been widely investigated in its effects on normal cells, there is little information concerning its effects on cancer cells. In the present study, the SMMC-7721 human liver cancer cell line treated with MCLR was used to investigate the change of PP2A, cytoskeleton rearrangement, phosphorylation levels of PP2A substrates that related with cytoskeleton stability and explored underlying mechanisms. Here, we confirmed that MCLR entered into SMMC-7721 cells, bound to PP2A/C subunit and inhibited the activity of PP2A. The upregulation of phosphorylation of the PP2A/C subunit and PP2A regulation protein α4, as well as the change in the association of PP2A/C with α4, were responsible for the decrease in PP2A activity. Another novel finding is that the rearrangement of filamentous actin and microtubules led by MCLR may attribute to the increased phosphorylation of HSP27, VASP and cofilin due to PP2A inhibition. As a result of weakened interactions with PP2A and alterations in its subcellular localization, Rac1 may contribute to the cytoskeletal rearrangement induced by MCLR in SMMC-7721 cells. The current paper presents the first report demonstrating the characteristic of PP2A in MCLR exposed cancer cells, which were more susceptible to MCLR compared with the normal cell lines we previously found, which may be owing to the absence of some type of compensatory mechanisms. The hyperphosphorylation of cytoskeleton-associated proteins and Rac1 inactivation which were induced by inhibition of PP2A are shown to be involved in cytoskeleton rearrangement.
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Affiliation(s)
- Hao 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
| | - Shuyan Lin
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Beilei Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Mingluan Xing
- 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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Chen L, Zhang X, Chen J, Zhang X, Fan H, Li S, Xie P. NF-κB plays a key role in microcystin-RR-induced HeLa cell proliferation and apoptosis. Toxicon 2014; 87:120-30. [PMID: 24932741 DOI: 10.1016/j.toxicon.2014.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 05/30/2014] [Accepted: 06/05/2014] [Indexed: 01/26/2023]
Abstract
Microcystins (MCs) are well-known cyanobacterial toxins produced in eutrophic waters and can act as potential carcinogens and have caused serious risk to human health. However, pleiotropic even paradoxical actions of cells exposure to MCs have been reported, and the mechanisms of MC-induced tumorigenesis and apoptosis are still unknown. In this study, we performed the first comprehensive in vitro investigation on carcinogenesis associated with nuclear factor kappa B (NF-κB) and its downstream genes in HeLa cells (Human cervix adenocarcinoma cell line from epithelial cells) exposure to MC-RR. HeLa cells were treated with 0, 20, 40, 60, and 80 µg/mL MC-RR for 4, 8, 12, and 24 h. HeLa cells presented dualistic responses to different doses of MCs. CCK8 assay showed that MC-RR exposure evidently enhanced cell viability of HeLa cells at lower MCs doses. Cell cycle and apoptosis analysis revealed that lower MCs doses promoted G1/S transition and cell proliferation while higher doses of MCs induced apoptosis, with a dose-dependent manner. Electrophoretic mobility shift assay (EMSA) revealed that MC-RR could increase/decrease NF-κB activity at lower/higher MC-RR doses, respectively. Furthermore, the expression of NF-κB downstream target genes including c-FLIP, cyclinD1, c-myc, and c-IAP2 showed the same variation trend as NF-κB activity both at mRNA and protein levels, which were induced by lower doses of MC-RR and suppressed by higher doses. Our data verified for the first time that NF-κB pathway may mediate MC-induced cell proliferation and apoptosis and provided a better understanding of the molecular mechanism for potential carcinogenicity of MC-RR.
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Affiliation(s)
- Liang Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xin Zhang
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jun Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Xuezhen Zhang
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Huihui Fan
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shangchun Li
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ping Xie
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China.
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22
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Roegner AF, Puschner B. Aggregate culture: A more accurate predictor of microcystin toxicity for risk assessment. Toxicon 2014; 83:1-14. [PMID: 24593965 DOI: 10.1016/j.toxicon.2014.02.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 02/15/2014] [Accepted: 02/20/2014] [Indexed: 10/25/2022]
Abstract
Aggregate or spheroid culture has emerged as a more biologically relevant method for screening pharmaceutical compounds and understanding exact mechanism of action. Here in, the aggregate approach applied to the freshwater toxins, microcystins, further unearths exact mechanism(s) of toxicity and provides a markedly improved in vitro predictor of toxicity. Microcystins result in acute intoxication by binding covalently to protein phosphatase 1/2A, resulting in hepatocellular necrosis, hemorrhaging and death. Hepatocellular uptake by organic anion transporting polypeptides (OATPs), in addition to other intracellular sequelae, is considered essential for toxicity. In aggregate HepG2, expression of OAT1B1 and OATP1B3 significantly increased relative to monolayer culture. Uptake of two fluorescently labeled substrates significantly increased in aggregates compared with monolayer, confirmed by inhibition of uptake with known competitive substrates. Increased reaction oxygen species (ROS) production occurred following a three-hour exposure of microcystin LR at concentrations from 100 nM to 100 μM, with reversal by ROS scavengers, in contrast with no response in monolayers. These results suggest monolayer culture inadequately predict intracellular effects of microcystins and support evidence that aggregate culture more closely approximates in vivo form and function. The approach results in more reliable prediction of microcystin toxicity in vitro.
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Affiliation(s)
- Amber F Roegner
- Department of Molecular Biosciences, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, University of California, Davis, CA 95616, USA
| | - Birgit Puschner
- Department of Molecular Biosciences, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, University of California, Davis, CA 95616, USA.
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Wang J, Lin F, Cai F, Yan W, Zhou Q, Xie L. Microcystin-LR inhibited hippocampal long-term potential via regulation of the glycogen synthase kinase-3β pathway. CHEMOSPHERE 2013; 93:223-229. [PMID: 23701903 DOI: 10.1016/j.chemosphere.2013.04.069] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 04/10/2013] [Accepted: 04/27/2013] [Indexed: 06/02/2023]
Abstract
We previously demonstrated that Cyanobacteria-derived microcystin-LR (MCLR) is able to induce cognitive dysfunction, but the mechanism is not understood. Long-term potential (LTP) in hippocampus is regarded as an important cellular mechanism of learning and memory. Here, the aim of this study was to evaluate the role of MCLR in LTP of hippocampal dentate gyrus (DG) by in vivo electrophysiological recording. We found that MCLR could suppress the induction of LTP in rat hippocampus, whereas simultaneous inhibition of glycogen synthase kinase-3β (GSK-3β) by LiCl or SB216763 attenuated the LTP impairments by MCLR. Furthermore, a decrease of the phosphorylated level at Ser9 of GSK-3β was observed by western blotting after intracerebroventricular (ICV) injection of MCLR, indicating GSK-3β was activated by MCLR. In addition, we showed that ICV administration of MCLR slightly stimulated activity of protein phosphatases (PPs) in the brain, which might activate GSK-3β via dephosphorylation of Ser9 site. Taken together, these findings demonstrated that GSK-3β plays a crucial role in regulating MCLR-induced cognitive deficit.
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Affiliation(s)
- Jianghua Wang
- College of Fisheries, Huazhong Agriculture University, Wuhan 430070, PR China
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Christen V, Meili N, Fent K. Microcystin-LR induces endoplasmatic reticulum stress and leads to induction of NFκB, interferon-alpha, and tumor necrosis factor-alpha. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:3378-3385. [PMID: 23431999 DOI: 10.1021/es304886y] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Microcystins (MCs) are hepatotoxins produced by cyanobacteria responsible for toxicity in humans and animals. Here, we investigate unexplored molecular pathways by which microcystin-LR (MC-LR) acts on hepatocytes to elucidate unknown modes of action. We focus on the endoplasmatic reticulum (ER) stress response or unfolded protein response (UPR), and on mechanisms that may contribute to the tumor-promoting effect of MCs in animals, including the activation of NFκB, the expression of interferon alpha (IFN-α) and the induction of interferon stimulated genes (ISGs), as well as the expression of tumor necrosis factor alpha (TNF-α). To this end, we exposed human hepatoma cells (Huh7) to 0.5 μM (nontoxic concentration), 5 μM (EC50 concentration), 25 μM and 50 μM (cytotoxic concentrations) MC-LR for 6, 24, 48, and 72 h. The expression of phosphatase 2A (PP2A) mRNA and protein was induced at 5 μM MC-LR. Phosphorylated P-CREB, a transcription factor for PP2A, leads to elevated expression of PP2A. Furthermore, all of the three ER stress pathways, the UPR and the endoplasmic reticulum-associated degradation were activated after exposure to 5, 25, and 50 μM MC-LR. Additionally, the expression of NFκB, IFN-α, and several INF-α-stimulated genes was strongly activated. The proinflammatory cytokine TNF-α was also induced. Our data demonstrate that MC-LR induces all ER stress response pathways. Consequently NFκB is activated, which in turn induces the expression of IFN-α and TNF-α. All of these activated pathways, which are analyzed here for the first time in detail, may contribute to the hepatotoxic, inflammatory, and tumorigenic action of MC-LR.
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Affiliation(s)
- Verena Christen
- University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland
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25
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Menezes C, Alverca E, Dias E, Sam-Bento F, Pereira P. Involvement of endoplasmic reticulum and autophagy in microcystin-LR toxicity in Vero-E6 and HepG2 cell lines. Toxicol In Vitro 2012; 27:138-48. [PMID: 23010415 DOI: 10.1016/j.tiv.2012.09.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/11/2012] [Accepted: 09/12/2012] [Indexed: 12/12/2022]
Abstract
This work investigates the involvement of the endoplasmic reticulum (ER) and autophagy in microcystin-LR (MCLR) toxicity in Vero-E6 and HepG2 cell lines. Additionally, morphological alterations induced by MCLR in lysosomes and mitochondria were studied. Cytotoxicity evaluation showed that pure MCLR and MCLR from LMECYA110 extract induce concentration dependent viability decays after 24h exposure. HepG2 cells showed an increased sensitivity to MCLR than Vero cells, with lower cytotoxic thresholds and EC(50) values. Conversely, LC3B immunofluorescence showed that autophagy is triggered in both cell lines as a survival response to low MCLR concentrations. Furthermore, MCLR induced a MCLR concentration-dependent decrease of GRP94 expression in HepG2 cells while in Vero cells no alteration was observed. This suggests the involvement of the ER in HepG2 apoptosis elicited by MCLR, while in Vero cells ER destructuration could be a consequence of cytoskeleton inflicted damages. Additionally, in both cell lines, lysosomal destabilization preceded mitochondrial impairment which occurred at high toxin concentrations. Although not an early cellular target of MCLR, mitochondria appears to serve as central mediators of different signaling pathways elicited by the organelles involved in MCLR toxicity. As a result, kidney and hepatic cell lines exhibit cell type and dose-dependent mechanisms to overcome MCLR toxicity.
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Affiliation(s)
- Carina Menezes
- Department of Environmental Health, National Health Institute Dr Ricardo Jorge, Av Padre Cruz, 1649-016 Lisbon, Portugal.
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Li T, Ying L, Wang H, Li N, Fu W, Guo Z, Xu L. Microcystin-LR Induces Ceramide to Regulate PP2A and Destabilize Cytoskeleton in HEK293 Cells. Toxicol Sci 2012; 128:147-57. [DOI: 10.1093/toxsci/kfs141] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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27
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Meng G, Sun Y, Fu W, Guo Z, Xu L. Microcystin-LR induces cytoskeleton system reorganization through hyperphosphorylation of tau and HSP27 via PP2A inhibition and subsequent activation of the p38 MAPK signaling pathway in neuroendocrine (PC12) cells. Toxicology 2011; 290:218-29. [DOI: 10.1016/j.tox.2011.09.085] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Revised: 09/23/2011] [Accepted: 09/28/2011] [Indexed: 11/16/2022]
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