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Guan PP, Cao LL, Yang Y, Wang P. Calcium Ions Aggravate Alzheimer's Disease Through the Aberrant Activation of Neuronal Networks, Leading to Synaptic and Cognitive Deficits. Front Mol Neurosci 2021; 14:757515. [PMID: 34924952 PMCID: PMC8674839 DOI: 10.3389/fnmol.2021.757515] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/04/2021] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disease that is characterized by the production and deposition of β-amyloid protein (Aβ) and hyperphosphorylated tau, leading to the formation of β-amyloid plaques (APs) and neurofibrillary tangles (NFTs). Although calcium ions (Ca2+) promote the formation of APs and NFTs, no systematic review of the mechanisms by which Ca2+ affects the development and progression of AD has been published. Therefore, the current review aimed to fill the gaps between elevated Ca2+ levels and the pathogenesis of AD. Specifically, we mainly focus on the molecular mechanisms by which Ca2+ affects the neuronal networks of neuroinflammation, neuronal injury, neurogenesis, neurotoxicity, neuroprotection, and autophagy. Furthermore, the roles of Ca2+ transporters located in the cell membrane, endoplasmic reticulum (ER), mitochondria and lysosome in mediating the effects of Ca2+ on activating neuronal networks that ultimately contribute to the development and progression of AD are discussed. Finally, the drug candidates derived from herbs used as food or seasoning in Chinese daily life are summarized to provide a theoretical basis for improving the clinical treatment of AD.
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Affiliation(s)
- Pei-Pei Guan
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Long-Long Cao
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Yi Yang
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Pu Wang
- College of Life and Health Sciences, Northeastern University, Shenyang, China
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2
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Abstract
Neuroelectrophysiology is an old science, dating to the 18th century when electrical activity in nerves was discovered. Such discoveries have led to a variety of neurophysiological techniques, ranging from basic neuroscience to clinical applications. These clinical applications allow assessment of complex neurological functions such as (but not limited to) sensory perception (vision, hearing, somatosensory function), and muscle function. The ability to use similar techniques in both humans and animal models increases the ability to perform mechanistic research to investigate neurological problems. Good animal to human homology of many neurophysiological systems facilitates interpretation of data to provide cause-effect linkages to epidemiological findings. Mechanistic cellular research to screen for toxicity often includes gaps between cellular and whole animal/person neurophysiological changes, preventing understanding of the complete function of the nervous system. Building Adverse Outcome Pathways (AOPs) will allow us to begin to identify brain regions, timelines, neurotransmitters, etc. that may be Key Events (KE) in the Adverse Outcomes (AO). This requires an integrated strategy, from in vitro to in vivo (and hypothesis generation, testing, revision). Scientists need to determine intermediate levels of nervous system organization that are related to an AO and work both upstream and downstream using mechanistic approaches. Possibly more than any other organ, the brain will require networks of pathways/AOPs to allow sufficient predictive accuracy. Advancements in neurobiological techniques should be incorporated into these AOP-base neurotoxicological assessments, including interactions between many regions of the brain simultaneously. Coupled with advancements in optogenetic manipulation, complex functions of the nervous system (such as acquisition, attention, sensory perception, etc.) can be examined in real time. The integration of neurophysiological changes with changes in gene/protein expression can begin to provide the mechanistic underpinnings for biological changes. Establishment of linkages between changes in cellular physiology and those at the level of the AO will allow construction of biological pathways (AOPs) and allow development of higher throughput assays to test for changes to critical physiological circuits. To allow mechanistic/predictive toxicology of the nervous system to be protective of human populations, neuroelectrophysiology has a critical role in our future.
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Affiliation(s)
- David W Herr
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, CPHEA/ORD, U.S. Environmental Protection Agency, Washington, NC, United States
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3
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Stanzione I, Izquierdo-Bote D, González García MB, Giardina P, Piscitelli A. Immobilization of Antibodies by Genetic Fusion to a Fungal Self-Assembling Adhesive Protein. Front Mol Biosci 2021; 8:725697. [PMID: 34738014 PMCID: PMC8561437 DOI: 10.3389/fmolb.2021.725697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/14/2021] [Indexed: 12/02/2022] Open
Abstract
Although antibody immobilization on solid surfaces is extensively used in several applications, including immunoassays, biosensors, and affinity chromatography, some issues are still challenging. Self-assembling protein layers can be used to coat easily different surfaces by direct deposition. A specific biofunctional layer can be formed using genetic engineering techniques to express fused proteins acting as self-immobilizing antibodies. In this study, fusion proteins combining the self-assembling adhesive properties of a fungal hydrophobin and the functionality of the single chain fragment variables (ScFvs) of two antibodies were produced. The chosen ScFvs are able to recognize marine toxins associated with algal blooms, saxitoxin, and domoic acid, which can bioaccumulate in shellfish and herbivorous fish causing food poisoning. ScFvs fused to hydrophobin Vmh2 from Pleurotus ostreatus were produced in Escherichia coli and recovered from the inclusion bodies. The two fusion proteins retained the functionality of both moieties, being able to adhere on magnetic beads and to recognize and bind the two neurotoxins, even with different performances. Our immobilization procedure is innovative and very easy to implement because it allows the direct functionalization of magnetic beads with ScFvs, without any surface modification. Two different detection principles, electrochemical and optical, were adopted, thus achieving a versatile platform suitable for different antigen detection methods. The sensitivity of the saxitoxin optical biosensor [limit of detection (LOD) 1.7 pg/ml] is comparable to the most sensitive saxitoxin immunosensors developed until now.
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4
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Shum S, Jing J, Petroff R, Crouthamel B, Grant KS, Burbacher TM, Isoherranen N. Maternal-fetal disposition of domoic acid following repeated oral dosing during pregnancy in nonhuman primate. Toxicol Appl Pharmacol 2020; 398:115027. [PMID: 32360744 PMCID: PMC7445014 DOI: 10.1016/j.taap.2020.115027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/22/2020] [Accepted: 04/26/2020] [Indexed: 01/17/2023]
Abstract
Domoic acid (DA) is a marine algal toxin that causes acute and chronic neurotoxicity in animals and humans. Prenatal exposure to DA has been associated with neuronal damage and cognitive and behavioral deficits in juvenile California sea lions, cynomolgus monkeys and rodents. Yet, the toxicokinetics (TK) of DA during pregnancy and the maternal-fetal disposition of DA have not been fully elucidated. In this study, we investigated the TK before, during, and after pregnancy and the maternal-fetal disposition of DA in 22 cynomolgus monkeys following daily oral doses of 0.075 or 0.15 mg/kg/day of DA. The AUC0-τ of DA was not changed while the renal clearance of DA was increased by 30-90% during and after pregnancy when compared to the pre-pregnancy values. DA was detected in the infant plasma and in the amniotic fluid at delivery. The infant plasma concentrations correlated positively with both the maternal plasma and the amniotic fluid concentrations. The paired infant-to-maternal plasma DA concentration ratios ranged from 0.3 to 0.6 and increased as a function of time which suggests placental efflux and longer apparent fetal half-life than the maternal half-life. The paired amniotic fluid-to-infant plasma DA concentration ratios ranged from 4.5 to 7.5 which indicates significant accumulation of DA in the amniotic fluid. A maternal-fetal TK model was developed to explore the processes that give the observed maternal-fetal disposition of DA. The final model suggests that placental transport and recirculation of DA between the fetus and amniotic fluid are major determining factors of the maternal-fetal TK of DA.
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Affiliation(s)
- Sara Shum
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Jing Jing
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA
| | - Rebekah Petroff
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Brenda Crouthamel
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Kimberly S Grant
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA; Infant Primate Research Laboratory, Washington National Primate Research Center, Seattle, Washington, USA
| | - Thomas M Burbacher
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA; Center on Human Development and Disability, University of Washington, Seattle, Washington, USA; Infant Primate Research Laboratory, Washington National Primate Research Center, Seattle, Washington, USA
| | - Nina Isoherranen
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA; Center on Human Development and Disability, University of Washington, Seattle, Washington, USA.
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5
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Gill S, Kumara VMR. Detecting Neurodevelopmental Toxicity of Domoic Acid and Ochratoxin A Using Rat Fetal Neural Stem Cells. Mar Drugs 2019; 17:md17100566. [PMID: 31590222 PMCID: PMC6835907 DOI: 10.3390/md17100566] [Citation(s) in RCA: 10] [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: 09/11/2019] [Revised: 10/01/2019] [Accepted: 10/02/2019] [Indexed: 12/12/2022] Open
Abstract
Currently, animal experiments in rodents are the gold standard for developmental neurotoxicity (DNT) investigations; however, testing guidelines for these experiments are insufficient in terms of animal use, time, and costs. Thus, alternative reliable approaches are needed for predicting DNT. We chose rat neural stem cells (rNSC) as a model system, and used a well-known neurotoxin, domoic acid (DA), as a model test chemical to validate the assay. This assay was used to investigate the potential neurotoxic effects of Ochratoxin A (OTA), of which the main target organ is the kidney. However, limited information is available regarding its neurotoxic effects. The effects of DA and OTA on the cytotoxicity and on the degree of differentiation of rat rNSC into astrocytes, neurons, and oligodendrocytes were monitored using cell-specific immunofluorescence staining for undifferentiated rNSC (nestin), neurospheres (nestin and A2B5), neurons (MAP2 clone M13, MAP2 clone AP18, and Doublecortin), astrocytes (GFAP), and oligodendrocytes (A2B5 and mGalc). In the absence of any chemical exposure, approximately 46% of rNSC differentiated into astrocytes and neurons, while 40% of the rNSC differentiated into oligodendrocytes. Both non-cytotoxic and cytotoxic concentrations of DA and OTA reduced the differentiation of rNSC into astrocytes, neurons, and oligodendrocytes. Furthermore, a non-cytotoxic nanomolar (0.05 µM) concentration of DA and 0.2 µM of OTA reduced the percentage differentiation of rNSC into astrocytes and neurons. Morphometric analysis showed that the highest concentration (10 μM) of DA reduced axonal length. These indicate that low, non-cytotoxic concentrations of DA and OTA can interfere with the differentiation of rNSC.
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Affiliation(s)
- S Gill
- Regulatory Toxicology Research Division, Health Products and Food Branch, Tunney's Pasture, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada.
| | - V M Ruvin Kumara
- Regulatory Toxicology Research Division, Health Products and Food Branch, Tunney's Pasture, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, ON K1A 0K9, Canada.
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6
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Bradley JA, Luithardt HH, Metea MR, Strock CJ. In Vitro Screening for Seizure Liability Using Microelectrode Array Technology. Toxicol Sci 2019; 163:240-253. [PMID: 29432603 DOI: 10.1093/toxsci/kfy029] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Drug-induced seizure liabilities produce significant compound attrition during drug discovery. Currently available in vitro cytotoxicity assays cannot predict all toxicity mechanisms due to the failure of these assays to predict sublethal target-specific electrophysiological liabilities. Identification of seizurogenic and other electrophysiological effects at early stages of the drug development process is important to ensure that safe candidate compounds can be developed while chemical design is taking place, long before these liabilities are discovered in costly preclinical in vivo studies. The development of a high throughput and reliable in vitro assay to screen compounds for seizure liabilities would de-risk compounds significantly earlier in the drug discovery process and with greater dependability. Here we describe a method for screening compounds that utilizes rat cortical neurons plated onto multiwell microelectrode array plates to identify compounds that cause neurophysiological disruptions. Changes in 12 electrophysiological parameters (spike train descriptors) were measured after application of known seizurogenic compounds and the response pattern was mapped relative to negative controls, vehicle control and neurotoxic controls. Twenty chemicals with a variety of therapeutic indications and targets, including GABAA antagonists, glycine receptor antagonists, ion channel blockers, muscarinic agonist, δ-opioid receptor agonist, dopaminergic D2/adrenergic receptor blocker and nonsteroidal anti-inflammatory drugs, were tested to assess this system. Sixteen of the seventeen seizurogenic/neurotoxic compounds tested positive for seizure liability or neurotoxicity, moreover, different endpoint response patterns for firing rate, burst characteristics and synchrony that distinguished the chemicals into groups relating to target and seizurogenic response emerged from the data. The negative and vehicle control compounds had no effect on neural activity. In conclusion, the multiwell microelectrode array platform using cryopreserved rat cortical neurons is a highly effective high throughput method for reliably screening seizure liabilities within an early de-risking drug development paradigm.
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Affiliation(s)
| | | | - Monica R Metea
- Cyprotex US, LLC, An Evotec Company, Watertown, Massachusetts
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7
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Shen L, Yang Q, He Y, Zou X, Cao Z. BmK NT1-induced neurotoxicity is mediated by PKC/CaMKⅡ-dependent ERK1/2 and p38 activation in primary cultured cerebellar granule cells. Toxicology 2019; 421:22-29. [PMID: 30940546 DOI: 10.1016/j.tox.2019.03.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 03/01/2019] [Accepted: 03/28/2019] [Indexed: 01/08/2023]
Abstract
Voltage-gated sodium channels (VGSCs) represent molecular targets for a number of potent neurotoxins that affect the ion permeation or gating kinetics. BmK NT1, an α-scorpion toxin purified from Buthus martensii Karch (BMK), induces excitatory neurotoxicity by activation of VGSCs with subsequent overloading of intracellular Ca2+ in cerebellar granule cells (CGCs). In the current study, we further investigated signaling pathways responsible for BmK NT1-induced neurotoxicity in CGCs. BmK NT1 exposure induced neuronal death in different development stages of CGCs with similar potencies ranging from 0.21-0.48 μM. The maximal neuronal death induced by BmK NT1 gradually increased from 25.6% at 7 days in vitro (DIVs) to 42.1%, 47.8%, and 67.2% at 10, 13, and 16 DIVs, respectively, suggesting that mature CGCs are more vulnerable to BmK NT1 exposure. Application of Ca2+/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) inhibitors, KN-62 or KN-93, but not Ca2+/calmodulin-dependent protein kinase kinase (CaMKK) inhibitor, STO-609, completely abolished BmK NT1-induced neuronal death. Moreover, BmK NT1 exposure stimulated CaMKⅡ phosphorylation. BmK NT1 also stimulated extracellular regulated protein kinases 1/2 (ERK1/2) and p38 phosphorylation which was abolished by tetrodotoxin demonstrating the role of VGSCs on BmK NT1-induced ERK1/2 and p38 phosphorylation. However, BmK NT1 didn't affect c-Jun N-terminal kinase (JNK) phosphorylation. In addition, both ERK1/2 inhibitor, U0126 and p38 inhibitor, SB203580 attenuated BmK NT1-induced neuronal death. Both PKC inhibitor, Gö 6983 and CaMKⅡ inhibitor, KN-62 abolished BmK NT1-induced ERK1/2 and p38 phosphorylation. Considered together, these data demonstrate that BmK NT1-induced neurotoxicity is through PKC/CaMKⅡ mediated ERK1/2 and p38 activation.
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Affiliation(s)
- Liping Shen
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Qundi Yang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Yuwei He
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Xiaohan Zou
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China.
| | - Zhengyu Cao
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China.
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8
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Pérez-Gómez A, Cabrera-García D, Warm D, Marini AM, Salas Puig J, Fernández-Sánchez MT, Novelli A. From the Cover: Selective Enhancement of Domoic Acid Toxicity in Primary Cultures of Cerebellar Granule Cells by Lowering Extracellular Na+ Concentration. Toxicol Sci 2019; 161:103-114. [PMID: 29029261 DOI: 10.1093/toxsci/kfx201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Domoic acid (DOM) is an excitatory amino acid analog of kainic acid (KA) that acts through glutamic acid (GLU) receptors, inducing a fast and potent neurotoxic response. Here, we present evidence for an enhancement of excitotoxicity following exposure of cultured cerebellar granule cells to DOM in the presence of lower than physiological Na+ concentrations. The concentration of DOM that reduced by 50% neuronal survival was approximately 3 µM in Na+-free conditions and 16 µM in presence of a physiological concentration of extracellular Na+. The enhanced neurotoxic effect of DOM was fully prevented by AMPA/KA receptor antagonist, while N-methyl-D-aspartate-receptor-mediated neurotoxicity did not seem to be involved, as the absence of extracellular Na+ failed to potentiate GLU excitotoxicity under the same experimental conditions. Lowering of extracellular Na+ concentration to 60 mM eliminated extracellular recording of spontaneous electrophysiological activity from cultured neurons grown on a multi electrode array and prevented DOM stimulation of the electrical activity. Although changes in the extracellular Na+ concentration did not alter the magnitude of the rapid increase in intracellular Ca2+ levels associated to DOM exposure, they did change significantly the contribution of voltage-sensitive calcium channels (VScaCs) and the recovery time to baseline. The prevention of Ca2+ influx via VSCaCs by nifedipine failed to prevent DOM toxicity at any extracellular Na+ concentration, while the reduction of extracellular Ca2+ concentration ameliorated DOM toxicity only in the absence of extracellular Na+, enhancing it in physiological conditions. Our data suggest a crucial role for extracellular Na+ concentration in determining excitotoxicity by DOM.
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Affiliation(s)
- Anabel Pérez-Gómez
- Department of Biochemistry and Molecular Biology, University of Oviedo, Oviedo, Spain
| | - David Cabrera-García
- Department of Biochemistry and Molecular Biology, University of Oviedo, Oviedo, Spain
| | - Davide Warm
- Department of Biochemistry and Molecular Biology, University of Oviedo, Oviedo, Spain
| | - Ann M Marini
- Department of Neurology and Program in Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Javier Salas Puig
- Unit of Epilepsy, Vall d'Hebrón Hospital, Barcelona, Spain.,Department of Medicine, University Autonoma of Barcelona, Barcelona, Spain
| | - Maria Teresa Fernández-Sánchez
- Department of Biochemistry and Molecular Biology, University of Oviedo, Oviedo, Spain.,University Institute of Biotechnology
| | - Antonello Novelli
- University Institute of Biotechnology.,Department of Psychology, University of Oviedo, Oviedo, Spain
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9
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Murk AJ, Nicolas J, Smulders FJ, Bürk C, Gerssen A. Marine biotoxins: types of poisoning, underlying mechanisms of action and risk management programmes. CHEMICAL HAZARDS IN FOODS OF ANIMAL ORIGIN 2019. [DOI: 10.3920/978-90-8686-877-3_09] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Albertinka J. Murk
- Department of Animal Sciences, Marine Animal Ecology group, Wageningen University and Research, P.O. Box 338, 6700 AH Wageningen, the Netherlands
| | - Jonathan Nicolas
- 68300 Saint-Louis, France, formerly affiliated with Division of Toxicology, Wageningen University and Research Centre, the Netherlands
| | - Frans J.M. Smulders
- Institute of Meat Hygiene, Meat Technology and Food Science, Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Christine Bürk
- Milchwirstschaftliche Untersuchungs- und Versuchsanstalt (MUVA) Kempten, GmbH, Ignaz-Kiechle-Straße 20-22, 87437 Kempten (Allgäu), Germany
| | - Arjen Gerssen
- RIKILT, Wageningen University & Research, P.O. Box 230, 6708 WB Wageningen, the Netherlands
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10
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Daguer H, Hoff RB, Molognoni L, Kleemann CR, Felizardo LV. Outbreaks, toxicology, and analytical methods of marine toxins in seafood. Curr Opin Food Sci 2018. [DOI: 10.1016/j.cofs.2018.10.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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11
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Radad K, Moldzio R, Al-Shraim M, Al-Emam A, Rausch WD. Long-term neurotoxic effects of domoic acid on primary dopaminergic neurons. Toxicol In Vitro 2018; 52:279-285. [PMID: 30017864 DOI: 10.1016/j.tiv.2018.07.004] [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] [Received: 03/10/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 10/28/2022]
Abstract
Domoic acid, an excitatory neurotoxin produced by certain algae, reaches the food chain through accumulation in some sea organisms. To investigate its long-term neurotoxicity on dopaminergic neurons, prepared primary mesencephalic cell cultures were exposed to different concentrations of domoic acid (0.1, 1, 10, 100 μM) on the 8th day in vitro (DIV) for 4 days. On the 12th DIV, culture media were collected for measurement of lactate dehydrogenase and cultured cells were subjected to immunohistochemistry against tyrosine hydroxylase, neuronal nuclear antigen and glial fibrillary acidic protein, and fluorescence staining using H2DCFDA, JC-1 and Hoechst 33342 dyes. Moreover, roles of AMPA/KA and NMDA receptors in domoic acid neurotoxicity were also investigated. Domoic acid significantly decreased the number of dopaminergic neurons and adversely affected their morphology, and slightly reduced the expression of neuronal nuclear antigen and glial fibrillary acidic protein. Co-treatment of cultures with domoic acid and the AMPA/KA or NMDA receptor antagonists NBQX and MK-801 rescued significant number of dopaminergic neurons. Domoic acid significantly decreased red:green fluorescence ratio of JC-1 and did not affect production of reactive oxygen species and apoptotic cell death. In conclusions, the present study reveals that long-term treatment of primary mesencephalic cell culture with domoic acid significantly destroyed dopaminergic neurons. This effect appears to be attributed to activation of AMPA/KA and NMDA receptors and mitochondrial damage.
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Affiliation(s)
- Khaled Radad
- Department of Pathology, College of Medicine, King Khalid University, Abha, Saudi Arabia; Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Assiut, Egypt.
| | - Rudolf Moldzio
- Department for Biomedical Sciences, Institute of Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
| | - Mubarak Al-Shraim
- Department of Pathology, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Ahmed Al-Emam
- Department of Pathology, College of Medicine, King Khalid University, Abha, Saudi Arabia; Forensic and Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Wolf-Dieter Rausch
- Department for Biomedical Sciences, Institute of Medical Biochemistry, University of Veterinary Medicine, Vienna, Austria
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12
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Progressive changes in hippocampal cytoarchitecture in a neurodevelopmental rat model of epilepsy: implications for understanding presymptomatic epileptogenesis, predictive diagnosis, and targeted treatments. EPMA J 2017; 8:247-254. [PMID: 29021835 DOI: 10.1007/s13167-017-0111-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 08/10/2017] [Indexed: 12/26/2022]
Abstract
Epilepsies affect about 4% of the population and are frequently characterized by a prolonged "silent" period before the onset of spontaneous seizures. Most current animal models of epilepsy either involve acute seizure induction or kindling protocols that induce repetitive seizures. We have developed a rat model of epilepsy that is characterized by a slowly progressing series of behavioral abnormalities prior to the onset of behavioral seizures. In the current study, we further describe an accompanying progression of cytoarchitectural changes in the hippocampal formation. Groups of male and female SD rats received serial injections of a low dose of domoic acid (0.020 mg/kg) (or vehicle) throughout the second week of life. Postmortem hippocampal tissue was obtained on postnatal days 29, 64, and 90 and processed for glial fibrillary acidic protein (GFAP), NeuN, and calbindin expression. The data revealed no significant changes on postnatal day (PND) 29 but a significant increase in hilar NeuN-positive cells in some regions on PND 64 and 90 that were identified as ectopic granule cells. Further, an increase in GFAP positive cell counts and evidence of reactive astrogliosis was found on PND 90 but not at earlier time points. We conclude that changes in cellular expression, possibly due to on-going non-convulsive seizures, develop slowly in this model and may contribute to progressive brain dysfunction that culminates in a seizure-prone phenotype.
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13
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Ramya EM, Kumar GP, Anand T, Anilakumar KR. Modulatory effects of Terminalia arjuna against domoic acid induced toxicity in Caco-2 cell line. Cytotechnology 2017; 69:725-739. [PMID: 28342004 DOI: 10.1007/s10616-017-0080-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 03/10/2017] [Indexed: 01/30/2023] Open
Abstract
Domoic acid is a potent marine algal toxin produced by diatomic genus of Pseudo-nitzschia causing amnesic shell fish poisoning. Domoic acid toxicosis mainly involves excitotoxic effects coupled with oxidative stress. The present study was aimed to evaluate the protective effects of hydro-alcoholic extract of Terminalia arjuna (TA) against domoic acid induced toxic effects in Caco-2 cell line. It was observed that the toxicity induced by domoic acid in Caco-2 cells was mediated by oxidative insult leading to morphological changes, DNA damage and apoptosis. In our study pre-treatment of the cells with TA (10, 20 and 30 μg/ml) showed significant protection against domoic acid induced morphological, oxidative and apoptotic damages in a dose dependent manner. The effect of phytocompounds present in TA viz., kaempferol and arjungenin showed significant protection against domoic acid induced toxicity in Caco-2 cell line. Hence, it could be inferred that the protective effect of TA extract against domoic acid induced toxicity could be due to the individual or synergistic effects of kaempferol and argungenin. However, further clinical studies are warranted to consider TA as a natural remedy to prevent amnesic shell fish poisoning.
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Affiliation(s)
- E M Ramya
- Applied Nutrition Division, Defence Food Research Laboratory (DRDO), Mysore, 570011, India
| | - G Phani Kumar
- Applied Nutrition Division, Defence Food Research Laboratory (DRDO), Mysore, 570011, India.
| | - T Anand
- Biochemistry and Nanosciences Division, DFRL, Mysore, 570011, India
| | - K R Anilakumar
- Applied Nutrition Division, Defence Food Research Laboratory (DRDO), Mysore, 570011, India
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14
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More SV, Kumar H, Cho DY, Yun YS, Choi DK. Toxin-Induced Experimental Models of Learning and Memory Impairment. Int J Mol Sci 2016; 17:E1447. [PMID: 27598124 PMCID: PMC5037726 DOI: 10.3390/ijms17091447] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 02/07/2023] Open
Abstract
Animal models for learning and memory have significantly contributed to novel strategies for drug development and hence are an imperative part in the assessment of therapeutics. Learning and memory involve different stages including acquisition, consolidation, and retrieval and each stage can be characterized using specific toxin. Recent studies have postulated the molecular basis of these processes and have also demonstrated many signaling molecules that are involved in several stages of memory. Most insights into learning and memory impairment and to develop a novel compound stems from the investigations performed in experimental models, especially those produced by neurotoxins models. Several toxins have been utilized based on their mechanism of action for learning and memory impairment such as scopolamine, streptozotocin, quinolinic acid, and domoic acid. Further, some toxins like 6-hydroxy dopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and amyloid-β are known to cause specific learning and memory impairment which imitate the disease pathology of Parkinson's disease dementia and Alzheimer's disease dementia. Apart from these toxins, several other toxins come under a miscellaneous category like an environmental pollutant, snake venoms, botulinum, and lipopolysaccharide. This review will focus on the various classes of neurotoxin models for learning and memory impairment with their specific mechanism of action that could assist the process of drug discovery and development for dementia and cognitive disorders.
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Affiliation(s)
- Sandeep Vasant More
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea.
| | - Hemant Kumar
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea.
| | - Duk-Yeon Cho
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea.
| | - Yo-Sep Yun
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea.
| | - Dong-Kug Choi
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju 27478, Korea.
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Lefebvre KA, Quakenbush L, Frame E, Huntington KB, Sheffield G, Stimmelmayr R, Bryan A, Kendrick P, Ziel H, Goldstein T, Snyder JA, Gelatt T, Gulland F, Dickerson B, Gill V. Prevalence of algal toxins in Alaskan marine mammals foraging in a changing arctic and subarctic environment. HARMFUL ALGAE 2016; 55:13-24. [PMID: 28073526 PMCID: PMC8276754 DOI: 10.1016/j.hal.2016.01.007] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 05/10/2023]
Abstract
Current climate trends resulting in rapid declines in sea ice and increasing water temperatures are likely to expand the northern geographic range and duration of favorable conditions for harmful algal blooms (HABs), making algal toxins a growing concern in Alaskan marine food webs. Two of the most common HAB toxins along the west coast of North America are the neurotoxins domoic acid (DA) and saxitoxin (STX). Over the last 20 years, DA toxicosis has caused significant illness and mortality in marine mammals along the west coast of the USA, but has not been reported to impact marine mammals foraging in Alaskan waters. Saxitoxin, the most potent of the paralytic shellfish poisoning toxins, has been well-documented in shellfish in the Aleutians and Gulf of Alaska for decades and associated with human illnesses and deaths due to consumption of toxic clams. There is little information regarding exposure of Alaskan marine mammals. Here, the spatial patterns and prevalence of DA and STX exposure in Alaskan marine mammals are documented in order to assess health risks to northern populations including those species that are important to the nutritional, cultural, and economic well-being of Alaskan coastal communities. In this study, 905 marine mammals from 13 species were sampled including; humpback whales, bowhead whales, beluga whales, harbor porpoises, northern fur seals, Steller sea lions, harbor seals, ringed seals, bearded seals, spotted seals, ribbon seals, Pacific walruses, and northern sea otters. Domoic acid was detected in all 13 species examined and had the greatest prevalence in bowhead whales (68%) and harbor seals (67%). Saxitoxin was detected in 10 of the 13 species, with the highest prevalence in humpback whales (50%) and bowhead whales (32%). Pacific walruses contained the highest concentrations of both STX and DA, with DA concentrations similar to those detected in California sea lions exhibiting clinical signs of DA toxicosis (seizures) off the coast of Central California, USA. Forty-six individual marine mammals contained detectable concentrations of both toxins emphasizing the potential for combined exposure risks. Additionally, fetuses from a beluga whale, a harbor porpoise and a Steller sea lion contained detectable concentrations of DA documenting maternal toxin transfer in these species. These results provide evidence that HAB toxins are present throughout Alaska waters at levels high enough to be detected in marine mammals and have the potential to impact marine mammal health in the Arctic marine environment.
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Affiliation(s)
- Kathi A Lefebvre
- Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, USA.
| | - Lori Quakenbush
- Alaska Department of Fish and Game, Arctic Marine Mammal Program, 1300 College Road, Fairbanks, AK, USA
| | - Elizabeth Frame
- Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, USA
| | - Kathy Burek Huntington
- Alaska Veterinary Pathology Services (AVPS), 23834 The Clearing Drive, Eagle River, AK, USA
| | - Gay Sheffield
- University of Alaska Fairbanks, Alaska Sea Grant, Marine Advisory Program, PO Box 400, Nome, AK, USA
| | - Raphaela Stimmelmayr
- North Slope Borough Department of Wildlife Management, PO Box 69, Barrow, AK, USA
| | - Anna Bryan
- Alaska Department of Fish and Game, Arctic Marine Mammal Program, 1300 College Road, Fairbanks, AK, USA
| | - Preston Kendrick
- Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, USA
| | - Heather Ziel
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA, Seattle, WA, USA
| | - Tracey Goldstein
- One Health Institute, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Jonathan A Snyder
- U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 East Tudor Rd., Anchorage, AK, USA
| | - Tom Gelatt
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA, Seattle, WA, USA
| | - Frances Gulland
- The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, CA, USA
| | - Bobette Dickerson
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA, Seattle, WA, USA
| | - Verena Gill
- U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 East Tudor Rd., Anchorage, AK, USA
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16
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Vieira AC, Cifuentes JM, Bermúdez R, Ferreiro SF, Castro AR, Botana LM. Heart Alterations after Domoic Acid Administration in Rats. Toxins (Basel) 2016; 8:E68. [PMID: 26978401 PMCID: PMC4810213 DOI: 10.3390/toxins8030068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/21/2016] [Accepted: 02/22/2016] [Indexed: 11/24/2022] Open
Abstract
Domoic acid (DA) is one of the best known marine toxins, causative of important neurotoxic alterations. DA effects are documented both in wildlife and experimental assays, showing that this toxin causes severe injuries principally in the hippocampal area. In the present study we have addressed the long-term toxicological effects (30 days) of DA intraperitoneal administration in rats. Different histological techniques were employed in order to study DA toxicity in heart, an organ which has not been thoroughly studied after DA intoxication to date. The presence of DA was detected by immunohistochemical assays, and cellular alterations were observed both by optical and transmission electron microscopy. Although histological staining methods did not provide any observable tissue damage, transmission electron microscopy showed several injuries: a moderate lysis of myofibrils and loss of mitochondrial conformation. This is the first time the association between heart damage and the presence of the toxin has been observed.
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Affiliation(s)
- Andres C Vieira
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo 27002, Spain.
| | - José Manuel Cifuentes
- Departamento de Anatomía, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo 27002, Spain.
| | - Roberto Bermúdez
- Departamento de Anatomía, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo 27002, Spain.
| | - Sara F Ferreiro
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo 27002, Spain.
| | - Albina Román Castro
- Rede de Infraestruturas de Apoio á Investigación e ao Desenvolvemento Tecnolóxico (RIADT) Lugo, Universidad de Santiago de Compostela, Lugo 27002, Spain.
| | - Luis M Botana
- Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo 27002, Spain.
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17
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Neely BA, Ferrante JA, Chaves JM, Soper JL, Almeida JS, Arthur JM, Gulland FMD, Janech MG. Proteomic Analysis of Plasma from California Sea Lions (Zalophus californianus) Reveals Apolipoprotein E as a Candidate Biomarker of Chronic Domoic Acid Toxicosis. PLoS One 2015; 10:e0123295. [PMID: 25919366 PMCID: PMC4412824 DOI: 10.1371/journal.pone.0123295] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 02/17/2015] [Indexed: 02/06/2023] Open
Abstract
Domoic acid toxicosis (DAT) in California sea lions (Zalophus californianus) is caused by exposure to the marine biotoxin domoic acid and has been linked to massive stranding events and mortality. Diagnosis is based on clinical signs in addition to the presence of domoic acid in body fluids. Chronic DAT further is characterized by reoccurring seizures progressing to status epilepticus. Diagnosis of chronic DAT is often slow and problematic, and minimally invasive tests for DAT have been the focus of numerous recent biomarker studies. The goal of this study was to retrospectively profile plasma proteins in a population of sea lions with chronic DAT and those without DAT using two dimensional gel electrophoresis to discover whether individual, multiple, or combinations of protein and clinical data could be utilized to identify sea lions with DAT. Using a training set of 32 sea lion sera, 20 proteins and their isoforms were identified that were significantly different between the two groups (p<0.05). Interestingly, 11 apolipoprotein E (ApoE) charge forms were decreased in DAT samples, indicating that ApoE charge form distributions may be important in the progression of DAT. In order to develop a classifier of chronic DAT, an independent blinded test set of 20 sea lions, seven with chronic DAT, was used to validate models utilizing ApoE charge forms and eosinophil counts. The resulting support vector machine had high sensitivity (85.7% with 92.3% negative predictive value) and high specificity (92.3% with 85.7% positive predictive value). These results suggest that ApoE and eosinophil counts along with machine learning can perform as a robust and accurate tool to diagnose chronic DAT. Although this analysis is specifically focused on blood biomarkers and routine clinical data, the results demonstrate promise for future studies combining additional variables in multidimensional space to create robust classifiers.
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Affiliation(s)
- Benjamin A. Neely
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States of America
| | - Jason A. Ferrante
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States of America
- Grice Marine Laboratory, College of Charleston, Charleston, SC, United States of America
| | - J. Mauro Chaves
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States of America
| | | | - Jonas S. Almeida
- Department of Biomedical Informatics, Stony Brook University, Long Island, NY, United States of America
| | - John M. Arthur
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States of America
- Research Service, Ralph H. Johnson VA Medical Center, Charleston, SC, United States of America
| | | | - Michael G. Janech
- Department of Medicine, Division of Nephrology, Medical University of South Carolina, Charleston, SC, United States of America
- Grice Marine Laboratory, College of Charleston, Charleston, SC, United States of America
- Research Service, Ralph H. Johnson VA Medical Center, Charleston, SC, United States of America
- * E-mail:
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18
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Vieira AC, Martínez JMC, Pose RB, Queijo ÁA, Posadas NA, López LMB. Dose-response and histopathological study, with special attention to the hypophysis, of the differential effects of domoic acid on rats and mice. Microsc Res Tech 2015; 78:396-403. [DOI: 10.1002/jemt.22486] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 01/09/2015] [Accepted: 02/14/2015] [Indexed: 12/17/2022]
Affiliation(s)
| | | | - Roberto Bermúdez Pose
- Departamento de Anatomía y Producción Animal; Facultad de Veterinaria; Lugo 27002 Spain
| | | | - Nuria Alemañ Posadas
- Departamento de Anatomía y Producción Animal; Facultad de Veterinaria; Lugo 27002 Spain
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Pizzo F, Caloni F, Schreiber NB, Schutz LF, Totty ML, Albonico M, Spicer LJ. Direct effects of the algal toxin, domoic acid, on ovarian function: Bovine granulosa and theca cells as an in vitro model. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 113:314-320. [PMID: 25528487 DOI: 10.1016/j.ecoenv.2014.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/27/2014] [Accepted: 12/02/2014] [Indexed: 06/04/2023]
Abstract
Domoic acid (DA) is a potent neurotoxin produced by alga Pseudo-nitzschia spp. and has been associated with reproductive disorders in mammals. The aim of this study was to investigate if DA can affect the reproductive system via direct action on ovarian function. Bovine granulosa and theca cells were used as in vitro models for evaluating DA effects on ovarian cell proliferation and steroid production. In small-follicle granulosa cells (SMGC), cell proliferation and estradiol (E2) production was not affected (P>0.05) while progesterone (P4) production was inhibited (P<0.05) by DA at all doses tested. In large-follicle granulosa cells (LGGC), DA had no effect (P>0.05) on cell proliferation or P4 production while E2 production was stimulated by 1 and 5 µg/ml DA (P<0.05). DA (1 µg/ml) attenuated (P<0.05) insulin-like growth factor 1 (IGF-1)-induced P4 production by large-follicle theca cells (LGTC), but did not affect androstenedione (A4) production or proliferation of LGTC. In glutamate-free medium, DA inhibited (P<0.05) SMGC E2 production and this inhibition was similar to inhibition of E2 by trans-(±)-1-amino-1,3-cyclopentanedicarboxylic acid monohydrate (ACPD; a selective metabotropic glutamate receptor subtype agonist) while kainic acid (KA; an ionotropic glutamate receptor subtype agonist) had no effect (P>0.10) on E2 production. Collectively, these results show for the first time that DA has direct effects on ovarian GC and TC steroidogenesis. Because DA inhibited E2 and P4 production, DA has the potential to be an endocrine disruptor.
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Affiliation(s)
- Fabiola Pizzo
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Via Celoria, 10 20133 Milan, Italy
| | - Francesca Caloni
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Via Celoria, 10 20133 Milan, Italy
| | - Nicole B Schreiber
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
| | - Luis F Schutz
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
| | - Morgan L Totty
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA
| | - Marco Albonico
- Department of Health, Animal Science and Food Safety, Università degli Studi di Milano, Via Celoria, 10 20133 Milan, Italy
| | - Leon J Spicer
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
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20
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Nicolas J, Hendriksen PJM, Gerssen A, Bovee TFH, Rietjens IMCM. Marine neurotoxins: State of the art, bottlenecks, and perspectives for mode of action based methods of detection in seafood. Mol Nutr Food Res 2013; 58:87-100. [DOI: 10.1002/mnfr.201300520] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/16/2013] [Accepted: 10/19/2013] [Indexed: 01/21/2023]
Affiliation(s)
- Jonathan Nicolas
- Division of Toxicology; Wageningen University; Wageningen The Netherlands
- RIKILT; Institute of Food Safety; Wageningen The Netherlands
| | | | - Arjen Gerssen
- RIKILT; Institute of Food Safety; Wageningen The Netherlands
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21
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Giordano G, Kavanagh TJ, Faustman EM, White CC, Costa LG. Low-level domoic acid protects mouse cerebellar granule neurons from acute neurotoxicity: role of glutathione. Toxicol Sci 2013; 132:399-408. [PMID: 23315585 PMCID: PMC3693515 DOI: 10.1093/toxsci/kft002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 12/28/2012] [Indexed: 11/14/2022] Open
Abstract
Domoic acid (DomA) is a potent marine neurotoxin. By activating α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid/kainate receptors, DomA induces oxidative stress-mediated apoptotic cell death in neurons. The effect of prolonged (10 days) exposure to a low, nontoxic concentration (5nM) of DomA on acute (intermediate concentration) neurotoxicity of this toxin was investigated in cerebellar granule neurons (CGNs) from wild-type mice and mice lacking the glutamate cysteine ligase (GCL) modifier subunit (Gclm (/)). CGNs from Gclm (/) mice have very low glutathione (GSH) levels and are very sensitive to DomA toxicity. In CGNs from wild-type mice, prolonged exposure to 5nM DomA did not cause any overt toxicity but reduced oxidative stress-mediated apoptotic cell death induced by exposure to an intermediate concentration (100nM for 24h) of DomA. This protection was not observed in CGNs from Gclm (/) mice. Prolonged DomA exposure increased GSH levels in CGNs of wild-type but not Gclm (/) mice. Levels of GCLC (the catalytic subunit of GCL) protein and mRNA were increased in CGNs of both mouse strains, whereas levels of GCLM protein and mRNA, activity of GCL, and levels of GCL holoenzyme were only increased in CGNs of wild-type mice. Chronic DomA exposure also protected wild-type CGNs from acute toxicity of other oxidants. The results indicate that CGNs from Gclm (/) mice, which are already more sensitive to DomA toxicity, are unable to upregulate their GSH levels. As Gclm (/) mice may represent a model for a common human polymorphism in GCLM, such individuals may be at particular risk for DomA-induced neurotoxicity.
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Affiliation(s)
- Gennaro Giordano
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington 98105, USA.
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22
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Tsunekawa K, Kondo F, Okada T, Feng GG, Huang L, Ishikawa N, Okada S. Enhanced expression of WD repeat-containing protein 35 (WDR35) stimulated by domoic acid in rat hippocampus: involvement of reactive oxygen species generation and p38 mitogen-activated protein kinase activation. BMC Neurosci 2013; 14:4. [PMID: 23289926 PMCID: PMC3548691 DOI: 10.1186/1471-2202-14-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 01/03/2013] [Indexed: 12/02/2022] Open
Abstract
Background Domoic acid (DA) is an excitatory amino acid analogue of kainic acid (KA) that acts via activation of glutamate receptors to elicit a rapid and potent excitotoxic response, resulting in neuronal cell death. Recently, DA was shown to elicit reactive oxygen species (ROS) production and induce apoptosis accompanied by activation of p38 mitogen-activated protein kinase (MAPK) in vitro. We have reported that WDR35, a WD-repeat protein, may mediate apoptosis in several animal models. In the present study, we administered DA to rats intraperitoneally, then used liquid chromatography/ion trap tandem mass spectrometry (LC-MS/MS) to identify and quantify DA in the brains of the rats and performed histological examinations of the hippocampus. We further investigated the potential involvement of glutamate receptors, ROS, p38 MAPK, and WDR35 in DA-induced toxicity in vivo. Results Our results showed that intraperitoneally administered DA was present in the brain and induced neurodegenerative changes including apoptosis in the CA1 region of the hippocampus. DA also increased the expression of WDR35 mRNA and protein in a dose- and time-dependent manner in the hippocampus. In experiments using glutamate receptor antagonists, the AMPA/KA receptor antagonist NBQX significantly attenuated the DA-induced increase in WDR35 protein expression, but the NMDA receptor antagonist MK-801 did not. In addition, the radical scavenger edaravone significantly attenuated the DA-induced increase in WDR35 protein expression. Furthermore, NBQX and edaravone significantly attenuated the DA-induced increase in p38 MAPK phosphorylation. Conclusion In summary, our results indicated that DA activated AMPA/KA receptors and induced ROS production and p38 MAPK phosphorylation, resulting in an increase in the expression of WDR35 in vivo.
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Affiliation(s)
- Koji Tsunekawa
- Department of Pharmacology, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan.
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23
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Maucher Fuquay J, Muha N, Wang Z, Ramsdell JS. Elimination Kinetics of Domoic Acid from the Brain and Cerebrospinal Fluid of the Pregnant Rat. Chem Res Toxicol 2012; 25:2805-9. [DOI: 10.1021/tx300434s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jennifer Maucher Fuquay
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
| | - Noah Muha
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
| | - Zhihong Wang
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
| | - John S. Ramsdell
- Marine Biotoxins
Program, Center for Coastal Environmental
Health and Biomolecular Research, NOAA, National Ocean Service, 219 Fort Johnson Road, Charleston, South Carolina
29412, United States
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Domoic Acid-Induced Neurotoxicity Is Mainly Mediated by the AMPA/KA Receptor: Comparison between Immature and Mature Primary Cultures of Neurons and Glial Cells from Rat Cerebellum. J Toxicol 2011; 2011:543512. [PMID: 22135676 PMCID: PMC3216357 DOI: 10.1155/2011/543512] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 08/24/2011] [Indexed: 11/18/2022] Open
Abstract
Domoic acid (DomA) is a naturally occurring shellfish toxin that can induce brain damage in mammalians. Neonates have shown increased sensitivity to DomA-induced toxicity, and prenatal exposure has been associated with e.g. decreased brain GABA levels, and increased glutamate levels. Here, we evaluated DomA-induced toxicity in immature and mature primary cultures of neurons and glial cells from rat cerebellum by measuring the mRNA levels of selected genes. Moreover, we assessed if the induced toxicity was mediated by the activation of the AMPA/KA and/or the NMDA receptor. The expression of all studied neuronal markers was affected after DomA exposure in both immature and mature cultures. However, the mature cultures seemed to be more sensitive to the treatment, as the effects were observed at lower concentrations and at earlier time points than for the immature cultures. The DomA effects were completely prevented by the antagonist of the AMPA/KA receptor (NBQX), while the antagonist of the NMDA receptor (APV) partly blocked the DomA-induced effects. Interestingly, the DomA-induced effect was also partly prevented by the neurotransmitter GABA. DomA exposure also affected the mRNA levels of the astrocytic markers in mature cultures. These DomA-induced effects were reduced by the addition of NBQX, APV, and GABA.
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25
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Cook P, Reichmuth C, Gulland F. Rapid behavioural diagnosis of domoic acid toxicosis in California sea lions. Biol Lett 2011; 7:536-8. [PMID: 21389016 DOI: 10.1098/rsbl.2011.0127] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Domoic acid is a neurotoxic metabolite of widely occurring algal blooms that has caused multiple marine animal stranding events. Exposure to high doses of domoic acid, a glutamate agonist, may lead to persistent medial temporal seizures and damage to the hippocampus. California sea lions (Zalophus californianus) are among the most visible and frequent mammalian victims of domoic acid poisoning, but rapid, reliable diagnosis in a clinical setting has proved difficult owing to the fast clearance of the toxin from the blood stream. Here, we show that the behavioural orienting responses of stranded sea lions diagnosed with domoic acid toxicosis habituate more slowly to a series of non-aversive auditory stimuli than do those of sea lions with no apparent neurological deficits. A signal detection analysis based on these habituation measures was able to correctly identify 50 per cent of subjects with domoic acid toxicosis while correctly rejecting approximately 93 per cent of controls, suggesting potential diagnostic merit.
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Affiliation(s)
- Peter Cook
- Department of Cognitive Psychology, University of California Santa Cruz, CA 95060, USA.
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26
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Ryan JC, Cross CA, Van Dolah FM. Effects of COX inhibitors on neurodegeneration and survival in mice exposed to the marine neurotoxin domoic acid. Neurosci Lett 2011; 487:83-7. [DOI: 10.1016/j.neulet.2010.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 10/01/2010] [Accepted: 10/01/2010] [Indexed: 02/02/2023]
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Application of micro-electrode arrays (MEAs) as an emerging technology for developmental neurotoxicity: evaluation of domoic acid-induced effects in primary cultures of rat cortical neurons. Neurotoxicology 2010; 32:158-68. [PMID: 21056592 DOI: 10.1016/j.neuro.2010.10.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 10/21/2010] [Accepted: 10/25/2010] [Indexed: 10/18/2022]
Abstract
Due to lack of knowledge only a few industrial chemicals have been identified as developmental neurotoxicants. Current developmental neurotoxicity (DNT) guidelines (OECD and EPA) are based entirely on in vivo studies that are both time consuming and costly. Consequently, there is a high demand to develop alternative in vitro methods for initial screening to prioritize chemicals for further DNT testing. One of the most promising tools for neurotoxicity assessment is the measurement of neuronal electrical activity using micro-electrode arrays (MEAs) that provides a functional and neuronal specific endpoint that until now has been used mainly to detect acute neurotoxicity. Here, electrical activity measurements were evaluated to be a suitable endpoint for the detection of potential developmental neurotoxicants. Initially, primary cortical neurons grown on MEA chips were characterized for different cell markers over time, using immunocytochemistry. Our results show that primary cortical neurons could be a promising in vitro model for DNT testing since some of the most critical neurodevelopment processes such as progenitor cell commitment, proliferation and differentiation of astrocytes and maturation of neurons are present. To evaluate if electrical activity could be a suitable endpoint to detect chemicals with DNT effects, our model was exposed to domoic acid (DomA), a potential developmental neurotoxicant for up to 4 weeks. Long-term exposure to a low concentration (50nM) of DomA increased the basal spontaneous electrical activity as measured by spike and burst rates. Moreover, the effect induced by the GABA(A) receptor antagonist bicuculline was significantly lower in the DomA treated cultures than in the untreated ones. The MEA measurements indicate that chronic exposure to DomA changed the spontaneous electrical activity leading to the possible neuronal mal functioning. The obtained results suggest that the MEAs could be a useful tool to identify compounds with DNT potential.
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Sawant PM, Tyndall JDA, Holland PT, Peake BM, Mountfort DO, Kerr DS. In vivo seizure induction and affinity studies of domoic acid and isodomoic acids-D, -E and -F. Neuropharmacology 2010; 59:129-38. [PMID: 20416329 DOI: 10.1016/j.neuropharm.2010.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 03/15/2010] [Accepted: 03/31/2010] [Indexed: 11/20/2022]
Abstract
Domoic acid and its isomers are produced via algal blooms and are found in high concentrations in shellfish. Here, we assessed the acute seizurogenic potencies of isomers-D, -E and -F and their binding affinities at heterogeneous populations of KA receptors from rat cerebrum. In addition, binding affinities of all six isomers (Iso-A through -F) were assessed at AMPA receptors. Radioligand displacement studies indicated that the seizurogenic potency of Iso-F (E-configuration) closely correlates with its affinities at both KA and AMPA receptors, whereas isomers-D (Z) and -E (E), which exhibit distinctly lower seizurogenic potencies, are quite weak displacers. Previously observed functional potencies for isomers-A, -B and -C (Sawant et al., 2008) correlated with AMPA receptor affinities observed here. Taken together, these findings call into question previous structure-activity rules. Significantly, in our hands, Iso-D was ten-fold less potent than Iso-F. To further explain observed links between structural conformation and functional potency, molecular modeling was employed. Modeling results closely matched the rank order of potency and binding data observed. We further assessed the efficacy of isomers-D, -E and -F as pharmacological preconditioning agents. Acute preconditioning with low-dose Iso-D, -E or -F, before high-dose DA failed to impart behavioural tolerance. This study has shed new light on structural conformations affecting non-NMDA ionotropic glutamate receptor binding and functional potency, and provides a foundation for future work in areas of AMPA and KA receptor modeling.
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Affiliation(s)
- P M Sawant
- Department of Pharmacology and Toxicology, University of Otago School of Medical Sciences, Dunedin, New Zealand.
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Costa LG, Giordano G, Faustman EM. Domoic acid as a developmental neurotoxin. Neurotoxicology 2010; 31:409-23. [PMID: 20471419 PMCID: PMC2934754 DOI: 10.1016/j.neuro.2010.05.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 05/04/2010] [Accepted: 05/05/2010] [Indexed: 11/21/2022]
Abstract
Domoic acid (DomA) is an excitatory amino acid which can accumulate in shellfish and finfish under certain environmental conditions. DomA is a potent neurotoxin. In humans and in non-human primates, oral exposure to a few mg/kg DomA elicits gastrointestinal effects, while slightly higher doses cause neurological symptoms, seizures, memory impairment, and limbic system degeneration. In rodents, which appear to be less sensitive than humans or non-human primates, oral doses cause behavioral abnormalities (e.g. hindlimb scratching), followed by seizures and hippocampal degeneration. Similar effects are also seen in other species (from sea lions to zebrafish), indicating that DomA exerts similar neurotoxic effects across species. The neurotoxicity of DomA is ascribed to its ability to interact and activate the AMPA/KA receptors, a subfamily of receptors for the neuroexcitatory neurotransmitter glutamate. Studies exploring the neurotoxic effects of DomA on the developing nervous system indicate that DomA elicits similar behavioral, biochemical and morphological effects as in adult animals. However, most importantly, developmental neurotoxicity is seen at doses of DomA that are one to two orders of magnitude lower than those exerting neurotoxicity in adults. This difference may be due to toxicokinetic and/or toxicodynamic differences. Estimated safe doses may be exceeded in adults by high consumption of shellfish contaminated with DomA at the current limit of 20 microg/g. Given the potential higher susceptibility of the young to DomA neurotoxicity, additional studies investigating exposure to, and effects of this neurotoxin during brain development are warranted.
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Affiliation(s)
- Lucio G Costa
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
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Lefebvre KA, Robertson A. Domoic acid and human exposure risks: A review. Toxicon 2010; 56:218-30. [DOI: 10.1016/j.toxicon.2009.05.034] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 05/06/2009] [Accepted: 05/13/2009] [Indexed: 01/20/2023]
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Phycotoxins: chemistry, mechanisms of action and shellfish poisoning. EXPERIENTIA SUPPLEMENTUM 2010; 100:65-122. [PMID: 20358682 DOI: 10.1007/978-3-7643-8338-1_3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Ruiz N, Petit K, Vansteelandt M, Kerzaon I, Baudet J, Amzil Z, Biard JF, Grovel O, Pouchus YF. Enhancement of domoic acid neurotoxicity on Diptera larvae bioassay by marine fungal metabolites. Toxicon 2009; 55:805-10. [PMID: 19941880 DOI: 10.1016/j.toxicon.2009.11.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 10/16/2009] [Accepted: 11/16/2009] [Indexed: 11/25/2022]
Abstract
Peptaibols are small linear fungal peptides which are produced in the marine environment. They exhibit neurotoxicity by forming pores in neuronal membranes. This work describes their combine effect with domoic acid, a neurotoxic phycotoxin, on Diptera larvae. The Acute toxicity bioassay on this biological model was tested with a panel of different toxins (microbial, algal or fungal). It allowed the discrimination of neurotoxins and non-neurotoxic toxins, and an evaluation of the toxicity level (MED and ED(50)) which were correlated with published LD(50) in mice for neurotoxins tested. The highest activities on this test were found for Na(+) channel blockers tetrodotoxin (ED(50) = 0.026 mg/kg) and saxitoxin (ED(50) = 0.18 mg/kg). Domoic acid was less active with an ED(50) = 7.6 mg/kg. For synergism study, longibrachin-A-I, a 20-mer peptaibol isolated from cultures of a marine-derived strain of Trichoderma longibrachiatum Rifai was chosen. Bioassay results confirmed its neuroactivity. Its level of toxicity (ED(50) = 270 mg/kg) was lower than those of phycotoxins tested but higher than mycotoxin ones. Injected together, longibrachin-A-I and domoic acid exhibited an increase of their activities. With doses of longibrachin-A-I below its Minimal Effective Dose (MED), the synergism factor which expresses the enhancement of domoic acid toxicity could reach 34.5. Both domoic acid and longibrachin-A-I are acting on ion channels and pores in neuronal membranes which contribute to the intake of Ca(2+) into cells.
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Affiliation(s)
- Nicolas Ruiz
- University of Nantes, Faculty of Pharmacy, MMS - EA 2160, F-44000 Nantes, France
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Immunomodulatory effects of domoic acid differ between in vivo and in vitro exposure in mice. Mar Drugs 2008; 6:636-59. [PMID: 19172200 PMCID: PMC2630849 DOI: 10.3390/md6040636] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 12/08/2008] [Accepted: 12/15/2008] [Indexed: 11/17/2022] Open
Abstract
The immunotoxic potential of domoic acid (DA), a well-characterized neurotoxin, has not been fully investigated. Phagocytosis and lymphocyte proliferation were evaluated following in vitro and in vivo exposure to assay direct vs indirect effects. Mice were injected intraperitoneally with a single dose of DA (2.5 μg/g b.w.) and sampled after 12, 24, or 48 hr. In a separate experiment, leukocytes and splenocytes were exposed in vitro to 0, 1, 10, or 100 μM DA. In vivo exposure resulted in a significant increase in monocyte phagocytosis (12-hr), a significant decrease in neutrophil phagocytosis (24-hr), a significant decrease in monocyte phagocytosis (48-hr), and a significant reduction in T-cell mitogen-induced lymphocyte proliferation (24-hr). In vitro exposure significantly reduced neutrophil and monocyte phagocytosis at 1 μM. B- and T-cell mitogen-induced lymphocyte proliferation were both significantly increased at 1 and 10 μM, and significantly decreased at 100 μM. Differences between in vitro and in vivo results suggest that DA may exert its immunotoxic effects both directly and indirectly. Modulation of cytosolic calcium suggests that DA exerts its effects through ionotropic glutamate subtype surface receptors at least on monocytes. This study is the first to identify DA as an immunotoxic chemical in a mammalian species.
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Lefebvre KA, Tilton SC, Bammler TK, Beyer RP, Srinouanprachan S, Stapleton PL, Farin FM, Gallagher EP. Gene expression profiles in zebrafish brain after acute exposure to domoic acid at symptomatic and asymptomatic doses. Toxicol Sci 2008; 107:65-77. [PMID: 18936300 DOI: 10.1093/toxsci/kfn207] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Domoic acid (DA) is a neuroexcitatory amino acid that is naturally produced by some marine diatom species of the genus Pseudo-nitzschia. Ingestion of DA-contaminated seafood by humans results in a severe neurotoxic disease known as amnesic shellfish poisoning (ASP). Clinical signs of ASP include seizures and neuronal damage from activation of ionotropic glutamate receptors. However, the impacts of DA exposure at levels below those known to induce outward signs of neurobehavioral exicitotoxicity have not been well characterized. To further understand the mechanisms of neurotoxic injury associated with DA exposure, we examined the transcriptome of whole brains from zebrafish (Danio rerio) receiving intracoelomic (IC) injection of DA at both symptomatic and asymptomatic doses. A majority of zebrafish exposed to high-dose DA (1.2 microg DA/g) exhibited clinical signs of neuroexcitotoxicity (EC(50) of 0.86 microg DA/g) within 5-20 min of IC injection. All zebrafish receiving low-dose DA (0.47 microg DA/g) or vehicle only maintained normal behavior. Microarray analysis of symptomatic and asymptomatic exposures collectively yielded 306 differentially expressed genes (1.5-fold, p </= 0.05) predominately represented by signal transduction, ion transport, and transcription factor functional categories. Transcriptional profiles were suggestive of neuronal apoptosis following an overwhelming of protective adaptive pathways. Further, potential molecular biomarkers of neuropathic injury, including the zebrafish homolog of human NDRG4, were identified and may be relevant to DA exposure levels below that causing neurobehavioral injury. In general, DA-modulated gene expression was consistent with other model species thereby validating zebrafish as an appropriate vertebrate model to study mechanisms of DA neurotoxicity. These data provide a basis for identifying pathways of DA-induced injury as well as biomarkers of asymptomatic and symptomatic DA exposure levels.
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Affiliation(s)
- Kathi A Lefebvre
- Marine Biotoxins Program, National Oceanic and Atmospheric Administration (NOAA) Fisheries/Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, Washington 98125, USA
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Domoic acid toxicologic pathology: a review. Mar Drugs 2008; 6:180-219. [PMID: 18728725 PMCID: PMC2525487 DOI: 10.3390/md20080010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 05/16/2008] [Accepted: 05/16/2008] [Indexed: 12/29/2022] Open
Abstract
Domoic acid was identified as the toxin responsible for an outbreak of human poisoning that occurred in Canada in 1987 following consumption of contaminated blue mussels [Mytilus edulis]. The poisoning was characterized by a constellation of clinical symptoms and signs. Among the most prominent features described was memory impairment which led to the name Amnesic Shellfish Poisoning [ASP]. Domoic acid is produced by certain marine organisms, such as the red alga Chondria armata and planktonic diatom of the genus Pseudo-nitzschia. Since 1987, monitoring programs have been successful in preventing other human incidents of ASP. However, there are documented cases of domoic acid intoxication in wild animals and outbreaks of coastal water contamination in many regions world-wide. Hence domoic acid continues to pose a global risk to the health and safety of humans and wildlife. Several mechanisms have been implicated as mediators for the effects of domoic acid. Of particular importance is the role played by glutamate receptors as mediators of excitatory neurotransmission and the demonstration of a wide distribution of these receptors outside the central nervous system, prompting the attention to other tissues as potential target sites. The aim of this document is to provide a comprehensive review of ASP, DOM induced pathology including ultrastructural changes associated to subchronic oral exposure, and discussion of key proposed mechanisms of cell/tissue injury involved in DOM induced brain pathology and considerations relevant to food safety and human health.
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Domoic acid induced spinal cord lesions in adult mice: evidence for the possible molecular pathways of excitatory amino acids in spinal cord lesions. Neurotoxicology 2008; 29:700-7. [PMID: 18534681 DOI: 10.1016/j.neuro.2008.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 03/23/2008] [Accepted: 04/11/2008] [Indexed: 11/24/2022]
Abstract
Domoic acid (DA) is an excitatory amino acids (EAAs) analog which induced excitotoxicity lesion to central nervous system, but whether induced adult animal spinal cord is not known, furthermore, previous studies have shown that EAAs play an important role in spinal cord lesion, however, the molecular pathways in spinal cord lesion are not fully known. Therefore, a motor neuron-like cell culture system and a DA-induced spinal cord lesioned mice model were used to study the effect of DA on spinal cord in adult mice and the possible molecular pathways of EAAs in spinal cord lesions. Exposure of motor neuron-like cells NSC34 to DA dramatically increased reactive oxygen species (ROS) production by the DCF fluorescent oxidation assay, reduced mitochondrial function by MTT assay, cell viability by trypan blue exclusion assay, and was accompanied by an increase of cell apoptosis by histone protein release assay. In DA-induced spinal cord lesioned mice model, we showed that the decrease of proteasome activity, increase of UCP4 expression by immunohistochemistry and neural cell apoptosis by TUNEL staining, and was accompanied by an decrease of motor disturbance grade during the different stages of DA treatment. Taken together, the in vitro and in vivo data presented in the current report demonstrated that DA induces spinal cord lesions in adult mice, and the multiple molecular pathways promoted by EAAs in spinal cord lesions, at least partially was associated with ROS generation increase, mitochondrial dysfunction, proteasome activity decrease and UCP4 expression increase.
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Lee CH, Hwang IK, Yoo KY, Choi JH, Park OK, Lee IS, Won MH. Parvalbumin immunoreactivity and protein level are altered in the gerbil hippocampus during normal aging. Neurochem Res 2008; 33:2222-8. [PMID: 18427987 DOI: 10.1007/s11064-008-9699-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 04/03/2008] [Indexed: 01/18/2023]
Abstract
Hippocampal interneurons are local circuit neurons which are responsible for inhibitory activity in the hippocampus. Parvalbumin (PV) is one of useful markers for GABAergic interneurons, not for principle cells, in the hippocampus. In the present study, we investigated age-related changes in PV immunoreactive neurons and protein levels in the gerbil hippocampus during normal aging. PV immunoreactive neurons were detected in all hippocampal subregions of all groups. PV immunoreactive neurons, which innervated principal neurons, were non-pyramidal neurons in the hippocampal CA1-3 regions, and were polymorphic neurons in the dentate gyrus. In the hippocampal CA1 region, the number of PV immunoreactive neurons was significantly reduced in the postnatal month 3 (PM 3) group, which was sustained by PM 18, and, at PM 24, the number of PV immunoreactive neurons was significantly decreased. In the CA2/3 region and dentate gyrus, the number of PV immunoreactive neurons was significantly decreased at PM 6: Thereafter, the number of PV immunoreactive neurons was sustained until PM 24. In addition, changes in PV protein levels in the gerbil hippocampus were similar to immunohistochemical changes during normal aging: PV protein levels were significantly decreased with age by PM 6: Thereafter, PV protein levels were sustained by PM 24. These results suggest that PV immunoreactive interneurons were decreased in the hippocampus with age in gerbils.
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Affiliation(s)
- Choong Hyun Lee
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul, 151-742, South Korea
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Bakke MJ, Horsberg TE. Effects of algal-produced neurotoxins on metabolic activity in telencephalon, optic tectum and cerebellum of Atlantic salmon (Salmo salar). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2007; 85:96-103. [PMID: 17870190 DOI: 10.1016/j.aquatox.2007.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 08/07/2007] [Accepted: 08/08/2007] [Indexed: 05/17/2023]
Abstract
Neurotoxins from algal blooms have been reported to cause mortality in a variety of species, including sea birds, sea mammals and fish. Farmed fish cannot escape harmful algal blooms and their potential toxins, thus they are more vulnerable for exposure than wild stocks. Sublethal doses of the toxins are likely to affect fish behaviour and may impair cognitive abilities. In the present study, changes in the metabolic activity in different parts of the Atlantic salmon (Salmo salar) brain involved in central integration and cognition were investigated after exposure to sublethal doses of three algal-produced neurotoxins; saxitoxin (STX), brevetoxin (BTX) and domoic acid (DA). Fish were randomly selected to four groups for i.p. injection of saline (control) or one of the neurotoxins STX (10 microg STX/kg bw), BTX (68 microg BTX/kg bw) or DA (6 mg DA/kg bw). In addition, 14C-2-deoxyglucose was i.m. injected to measure brain metabolic activity by autoradiography. The three regions investigated were telencephalon (Tel), optic tectum (OT) and cerebellum (Ce). There were no differences in the metabolic activity after STX and BTX exposure compared to the control in these regions. However, a clear increase was observed after DA exposure. When the subregions with the highest metabolic rate were pseudocoloured in the three brain regions, the three toxins caused distinct differences in the respective patterns of metabolic activation. Fish exposed to STX displayed similar patterns as the control fish, whereas fish exposed to BTX and DA showed highest metabolic activity in subregions different from the control group. All three neurotoxins affected subregions that are believed to be involved in cognitive abilities in fish.
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Affiliation(s)
- Marit Jørgensen Bakke
- Department of Pharmacology and Toxicology, Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway
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Giordano G, White CC, Mohar I, Kavanagh TJ, Costa LG. Glutathione levels modulate domoic acid induced apoptosis in mouse cerebellar granule cells. Toxicol Sci 2007; 100:433-44. [PMID: 17804861 DOI: 10.1093/toxsci/kfm236] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Exposure of mouse cerebellar granule neurons (CGNs) to domoic acid induced cell death, either by apoptosis or by necrosis, depending on its concentration. Necrotic damage predominated in response to domoic acid above 0.1 microM. In contrast, cell injury with apoptotic features (assessed by Hoechst staining and DNA laddering assay) was evident after exposure to lower concentrations of domoic acid (< or = 0.1 microM). The AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)/kainate receptor antagonist 2,3-dihydroxy-6-nitro-sulfamoylbenzo [f] quinoxaline, but not the N-methyl-D-aspartate receptor antagonist MK-801, prevented domoic acid-induced apoptosis. To evaluate the role of oxidative stress in domoic acid-induced apoptosis, experiments were carried out in CGNs isolated from wild-type mice (Gclm (+/+)) and mice lacking the modifier subunit of glutamate-cysteine ligase, the first and rate-limiting step of glutathione (GSH) biosynthesis (Gclm (-/-)). CGNs from Gclm (-/-) mice have very low levels of GSH and were more sensitive to domoic acid-induced apoptosis and necrosis than Gclm (+/+) CGNs. The antioxidant melatonin (200 microM) and the membrane-permeant GSH delivery agent GSH ethyl ester (2.5 mM) prevented domoic acid-induced apoptosis. Domoic acid increased formation of reactive oxygen species but did not affect intracellular GSH levels. Domoic acid also increased cytosolic and mitochondrial calcium levels, increased oxidative stress in mitochondria, and altered mitochondrial membrane potential, which ultimately caused cytochrome c release, activation of caspase-3, and degradation of poly (ADP-ribose) polymerase. These results indicate that low concentrations of domoic acid cause apoptotic neuronal cell death mediated by oxidative stress.
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Affiliation(s)
- Gennaro Giordano
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA
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Giordano G, White CC, McConnachie LA, Fernandez C, Kavanagh TJ, Costa LG. Neurotoxicity of domoic Acid in cerebellar granule neurons in a genetic model of glutathione deficiency. Mol Pharmacol 2006; 70:2116-26. [PMID: 17000861 DOI: 10.1124/mol.106.027748] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
This study investigated the role of cellular antioxidant defense mechanisms in modulating the neurotoxicity of domoic acid (DomA), by using cerebellar granule neurons (CGNs) from mice lacking the modifier subunit of glutamate-cysteine ligase (Gclm). Glutamate-cysteine ligase (Glc) catalyzes the first and rate-limiting step in glutathione (GSH) biosynthesis. CGNs from Gclm (-/-) mice have very low levels of GSH and are 10-fold more sensitive to DomA-induced toxicity than CGNs from Gclm (+/+) mice. GSH ethyl ester decreased, whereas the Gcl inhibitor buthionine sulfoximine increased DomA toxicity. Antagonists of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate receptors and of N-methyl-D-aspartate (NMDA) receptors blocked DomA toxicity, and NMDA receptors were activated by DomA-induced l-glutamate release. The differential susceptibility of CGNs to DomA toxicity was not due to a differential expression of ionotropic glutamate receptors, as evidenced by similar calcium responses and L-glutamate release in the two genotypes. A calcium chelator and several antioxidants antagonized DomA-induced toxicity. DomA caused a rapid decrease in cellular GSH, which preceded toxicity, and the decrease was primarily due to DomA-induced GSH efflux. DomA also caused an increase in oxidative stress as indicated by increases in reactive oxygen species and lipid peroxidation, which was subsequent to GSH efflux. Astrocytes from both genotypes were resistant to DomA toxicity and presented a diminished calcium response to DomA and a lack of DomA-induced L-glutamate release. Because polymorphisms in the GCLM gene in humans are associated with low GSH levels, such individuals, as well as others with genetic conditions or environmental exposures that lead to GSH deficiency, may be more susceptible to DomA-induced neurotoxicity.
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Affiliation(s)
- G Giordano
- Department of Environmental and Occupational Health Sciences, University of Washington, 4225 Roosevelt Way NE, Suite 100, Seattle, WA 98105, USA
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Vale-González C, Alfonso A, Suñol C, Vieytes MR, Botana LM. Role of the plasma membrane calcium adenosine triphosphatase on domoate-induced intracellular acidification in primary cultures of cerebelar granule cells. J Neurosci Res 2006; 84:326-37. [PMID: 16634067 DOI: 10.1002/jnr.20878] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Changes in intracellular pH (pH(i)) and cytosolic calcium concentration ([Ca(2+)](c)) caused by the glutamate agonist domoate (DOM) were studied in single cultured mouse cerebellar granule cells (CGC) by using the fluorescent probes 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and simultaneous evaluation of cytosolic calcium concentration with the fluorescent dye Fura-2 acetoxymethyl ester (Fura-2 AM). DOM caused a concentration-dependent increase in [Ca(2+)](c) and a concentration-dependent intracellular acidification of CGC. DOM-induced intracellular acidification was completely abolished by the use of Ca(2+)-free medium, suggesting that it was due mostly to an influx of extracellular calcium. The pH(i) decrease caused by DOM was also completely blocked in the presence of the AMPA/kainate receptor antagonist CNQX, indicating that the DOM-induced intracellular acidification was caused by DOM activation of the AMPA/kainate subtype of glutamate receptors. Different mechanisms that could be involved in DOM-induced pH(i) decrease, such as displacement of H(+) by Ca(2+) from a common intracellular binding site, DOM-induced alteration of pH(i) regulation mechanisms, and a possible acidification caused by DOM-induced increase of mitochondrial Ca(2+) uptake, were excluded. DOM-induced intracellular acidification was completely prevented by inhibitors of the plasma membrane calcium adenosine triphosphatase (ATPase) (PMCA), including orthovanadate, lanthanum extracellular pH of 8.5, and the specific PMCA inhibitor caloxin 2A1. Our results therefore indicate that PMCA is involved in DOM-induced intracellular acidification in primary cultures of CGC. Simultaneous recording of [Ca(2+)](c) and pH(i) indicates that the increase in intracellular calcium evoked by DOM will activate the calcium extrusion mechanisms through the calcium pump, which, in turn, will decrease intracellular pH by countertransport of H(+) ions.
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Affiliation(s)
- Carmen Vale-González
- Departamento de Farmacología, Facultad de Veterinaria, USC, Campus Universitario s/n, Lugo, Spain
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Vale C, Alfonso A, Suñol C, Vieytes MR, Botana LM. Modulation of calcium entry and glutamate release in cultured cerebellar granule cells by palytoxin. J Neurosci Res 2006; 83:1393-406. [PMID: 16547972 DOI: 10.1002/jnr.20841] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A channel open on the membrane can be formed by palytoxin (PTX). Ten nanomolar PTX caused an irreversible increase in the cytosolic calcium concentration ([Ca(2+)](c)), which was abolished in the absence of external calcium. The increase was eliminated by saxitoxin (STX) and nifedipine (NIF). Calcium rise is secondary to the membrane depolarization. PTX effect on calcium was dependent on extracellular Na(+). Li(+) decreased the PTX-evoked rise in [Ca(2+)](c); replacement of Na(+) by N-methyl-D-glucamine (NMDG) abolished PTX-induced calcium increase. [Ca(2+)](c) increase by PTX was strongly reduced after inhibition of the reverse operation of the Na(+)/Ca(2+) exchanger, in the presence of antagonists of excitatory amino acid (EAA) receptors, and by inhibition of neurotransmitter release. PTX did not modify calcium extrusion by the plasma membrane Ca(2+)-ATPase (PMCA), because blockade of the calcium pump increased rather than decreased the PTX-induced calcium influx. Extracellular levels of glutamate and aspartate were measured by HPLC and exocytotic neurotransmitter release by determination of synaptic vesicle exocytosis using total internal reflection fluorescence microscopy (TIRFM). PTX caused a concentration-dependent increase in EAA release to the culture medium. Ten nanomolar PTX decreased cell viability by 30% within 5 min. PTX-induced calcium influx involves three pathways: Na(+)-dependent activation of voltage-dependent sodium channels (VDSC) and voltage-dependent calcium channels (VDCC), reverse operation of the Na(+)/Ca(2+) exchanger, and indirect activation of EAA receptors through glutamate release. The neuronal injury produced by the toxin could be partially mediated by the PTX-induced overactivation of EAA receptors, VDSC, VDCC and the glutamate efflux into the extracellular space.
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Affiliation(s)
- Carmen Vale
- Departamento de Farmacología, Facultad de Veterinaria, USC, Campus Universitario, Lugo, Spain
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Qiu S, Currás-Collazo MC. Histopathological and molecular changes produced by hippocampal microinjection of domoic acid. Neurotoxicol Teratol 2006; 28:354-62. [PMID: 16529907 DOI: 10.1016/j.ntt.2006.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2005] [Revised: 01/03/2006] [Accepted: 01/26/2006] [Indexed: 11/19/2022]
Abstract
The phytoplankton-derived neurotoxin, domoic acid (DOM), frequently causes poisoning of marine animals and poses an increasing threat to public health through contamination of seafood. In this study, we used stereotactic microinjection technique to administer varying amounts of DOM into the hippocampal CA1 region in order to examine potential histopathological changes after injection of sub-lethal concentrations to CA1 pyramidal neurons. Gross anatomical abnormalities in CA1 were observed at above 10 microM DOM (3 pmol in 0.3 microl saline). At 1mM concentration, DOM produces both ipsilateral and contralateral neuronal cell death in CA1, CA3 as well as dentate gyrus subfields. Animal behavioral changes after microinjection were similar to those observed by previous studies through systemic DOM injection. Neuronal degeneration was paralleled by reduced glutamate receptor (NR1, GluR1 and GluR6/7) immunolabeling throughout the whole hippocampal formation. Pre-injection of the AMPA/KA receptor antagonist NBQX (10 microM, 0.3 microl) blocked 1mM DOM-induced neuronal degeneration as well as behavioral symptoms. At concentrations lower than 10 microM, no histopathological changes were observed microscopically, nor were the levels of immunostaining of NR1, GluR1, GluR6/7 different. However, increased immunolabeling of autophosphorylated calcium-calmodulin-dependent kinase II (CaMKII, p-Thr286) and phosphorylated cAMP response element binding protein (CREB, p-Ser133) were observed at 24 h post-injection, suggesting that altered intracellular signal transduction mediated by GluRs might be an adaptive cellular protective mechanism against DOM-induced neurotoxicity.
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Affiliation(s)
- Shenfeng Qiu
- Environmental Toxicology Graduate Program, University of California, Riverside, USA.
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Qiu S, Pak CW, Currás-Collazo MC. Sequential involvement of distinct glutamate receptors in domoic acid-induced neurotoxicity in rat mixed cortical cultures: effect of multiple dose/duration paradigms, chronological age, and repeated exposure. Toxicol Sci 2005; 89:243-56. [PMID: 16221958 DOI: 10.1093/toxsci/kfj008] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The increasing occurrence of poisoning accidents in marine animals caused by the amnesic shellfish toxin, domoic acid (DOM), necessitates a better understanding of the factors contributing to DOM neurotoxicity. Here we evaluated the contribution and temporal involvement of NMDA, non-NMDA- and metabotropic-type glutamate receptors (GluRs) in DOM-induced neuronal death using rat primary mixed cortical cultures. Co-application of antagonists for AMPA/kainate- (NBQX) and NMDA-type GluRs (D-AP5) but not for metabotropic GluRs reduced DOM toxicity induced by either of three EC50 dose/duration exposure paradigms. Maximal protection offered by D-AP5 and NBQX either extended or not to the 30- to 60-min period after DOM exposure, respectively. Antagonists were ineffective if applied with a 2-h delay, indicating the presence of a critical time window for neuronal protection after DOM exposure. Early effects correlated with neuronal swelling was seen as early as 10 min post-DOM, which has been linked to non-NMDAR-mediated depolarization and release of endogenous glutamate. That DOM toxicity is dictated by iGluRs is supported by the finding that increased efficacy and potency of DOM with in vitro neuronal maturation are positively correlated with elevated protein levels of iGluR subunits, including NR1, GluR1, GluR2/3, GluR5, and GluR6/7. We determined the time course of DOM excitotoxicity. At >10 microM maximal neuronal death occurs within 2 h, while doses < or = 10 microM continue to produce death during the subsequent 22-h washout period, indicating a quicker progression of the neuronal death cascade with high DOM concentrations. Accordingly, NBQX applied 30 min post-DOM afforded better protection against low dose/prolonged duration (3 microM/24 h) than against high dose/brief duration exposure (50 microM/10 min). Interestingly, prior exposure to subthreshold DOM dose-dependently aggravated toxicity produced by a subsequent exposure to DOM. These findings provide greater insight into the complex properties underlying DOM toxicity, including the sequential involvement of multiple GluRs, greater potency with increasing neuronal maturation and protein levels of iGluRs, varying efficacy depending on dose, duration, and prior history of DOM exposure.
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Affiliation(s)
- Shenfeng Qiu
- Environmental Toxicology Graduate Program, University of California at Riverside, Riverside, California 92521, USA
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Ryan JC, Morey JS, Ramsdell JS, Van Dolah FM. Acute phase gene expression in mice exposed to the marine neurotoxin domoic acid. Neuroscience 2005; 136:1121-32. [PMID: 16216424 DOI: 10.1016/j.neuroscience.2005.08.047] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Revised: 07/11/2005] [Accepted: 08/15/2005] [Indexed: 11/23/2022]
Abstract
Domoic acid is a rigid analog of the neurotransmitter glutamate and a potent agonist of kainate subtype glutamate receptors. Persistent activation of these receptor subtypes results in rapid excitotoxicity, calcium dependent cell death and neuronal lesions in areas of the brain where kainate pathways are concentrated. To better understand responses to domoic acid induced excitotoxicity, microarrays were used to profile gene expression in mouse brain following domoic acid exposure. Adult female mice were subjected intraperitoneally to domoic acid at the lethal dose 50, killed and dissected at 30, 60 and 240 min post-injection. Total brain RNA from treated mice was compared with time-matched controls on Agilent 22K feature microarrays. Real-time PCR was performed on selected genes. For the 30, 60 and 240 min time points, 3.96%, 3.94% and 4.36% of the genes interrogated were differentially expressed (P-value < or = 0.01), respectively. Rigorous filtering of the data resulted in a set of 56 genes used for trending analysis and K-medians and agglomerative clustering. The earliest genes induced consisted primarily of early response gene families (Jun, Fos, Ier, Egr, growth arrest and DNA damage 45) and the inflammatory response element cyclooxygenase 2. Some later responding genes involved glucocorticoid responses (Gilz, Sgk), cold inducible proteins (Cirbp, Rbm3), Map kinases (Map3k6) and NF-kappaB inhibition. Real-time PCR in male mice from an additional study confirmed the expression of several of these genes across gender. The transcriptional profile induced by domoic acid shared similarity with expression profiles of brain ischemia and other excitotoxins, suggesting a common transcriptional response.
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Affiliation(s)
- J C Ryan
- Marine Biotoxins Program, NOAA/National Ocean Service Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, SC 29412, USA.
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Colman JR, Nowocin KJ, Switzer RC, Trusk TC, Ramsdell JS. Mapping and reconstruction of domoic acid-induced neurodegeneration in the mouse brain. Neurotoxicol Teratol 2005; 27:753-67. [PMID: 16109471 DOI: 10.1016/j.ntt.2005.06.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Accepted: 02/28/2005] [Indexed: 11/16/2022]
Abstract
Domoic acid, a potent neurotoxin and glutamate analog produced by certain species of the marine diatom Pseudonitzschia, is responsible for several human and wildlife intoxication events. The toxin characteristically damages the hippocampus in exposed humans, rodents, and marine mammals. Histochemical studies have identified this, and other regions of neurodegeneration, though none have sought to map all brain regions affected by domoic acid. In this study, mice exposed (i.p.) to 4 mg/kg domoic acid for 72 h exhibited behavioral and pathological signs of neurotoxicity. Brains were fixed by intracardial perfusion and processed for histochemical analysis. Serial coronal sections (50 microm) were stained using the degeneration-sensitive cupric silver staining method of DeOlmos. Degenerated axons, terminals, and cell bodies, which stained black, were identified and the areas of degeneration were mapped onto Paxinos mouse atlas brain plates using Adobe Illustrator CS. The plates were then combined to reconstruct a 3-dimensional image of domoic acid-induced neurodegeneration using Amira 3.1 software. Affected regions included the olfactory bulb, septal area, and limbic system. These findings are consistent with behavioral and pathological studies demonstrating the effects of domoic acid on cognitive function and neurodegeneration in rodents.
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Affiliation(s)
- J R Colman
- Marine Biotoxins Program, Coastal Research Branch, Center for Coastal Environmental Health and Biomolecular Research, NOAA-National Ocean Service, 219 Fort Johnson Rd., Charleston, SC 29412, USA
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Kreuder C, Miller MA, Lowenstine LJ, Conrad PA, Carpenter TE, Jessup DA, Mazet JAK. Evaluation of cardiac lesions and risk factors associated with myocarditis and dilated cardiomyopathy in southern sea otters (Enhydra lutris nereis). Am J Vet Res 2005; 66:289-99. [PMID: 15757130 DOI: 10.2460/ajvr.2005.66.289] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To describe cardiac lesions and identify risk factors associated with myocarditis and dilated cardiomyopathy (DCM) in beach-cast southern sea otters. ANIMALS Free-ranging southern sea otters. PROCEDURE Sea otters were necropsied at the Marine Wildlife Veterinary Care and Research Center from 1998 through 2001. Microscopic and gross necropsy findings were used to classify sea otters as myocarditis or DCM case otters or control otters. Univariate, multivariate, and spatial analytical techniques were used to evaluate associations among myocarditis; DCM; common sea otter pathogens; and potential infectious, toxic, and nutritional causes. RESULTS Clusters of sea otters with myocarditis and DCM were identified in the southern aspect of the sea otter range from May to November 2000. Risk factors for myocarditis included age, good body condition, and exposure to domoic acid and Sarcocystis neurona. Myocarditis associated with domoic acid occurred predominantly in the southern part of the range, whereas myocarditis associated with S. neurona occurred in the northern part of the range. Age and suspected previous exposure to domoic acid were identified as major risk factors for DCM. A sample of otters with DCM had significantly lower concentrations of myocardial L-carnitine than control and myocarditis case otters. CONCLUSIONS AND CLINICAL RELEVANCE Cardiac disease is an important cause of death in southern sea otters. Domoic acid toxicosis and infection with S. neurona are likely to be 2 important causes of myocarditis in sea otters. Domoic acid-induced myocarditis appears to progress to DCM, and depletion of myocardial L-carnitine may play a key role in this pathogenesis.
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Affiliation(s)
- Christine Kreuder
- Wildlife Heath Center, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Kanai H, Sawa A, Chen RW, Leeds P, Chuang DM. Valproic acid inhibits histone deacetylase activity and suppresses excitotoxicity-induced GAPDH nuclear accumulation and apoptotic death in neurons. THE PHARMACOGENOMICS JOURNAL 2005; 4:336-44. [PMID: 15289798 DOI: 10.1038/sj.tpj.6500269] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Valproic acid (VPA), used to treat bipolar mood disorder and seizures, also inhibits histone deacetylase (HDAC). Here, we found that VPA and other HDAC inhibitors, butyrate and trichostatin A, robustly protected mature cerebellar granule cell cultures from excitotoxicity induced by SYM 2081 ((2S, 4R)-4-methylglutamate), an inhibitor of excitatory amino-acid transporters and an agonist of low-affinity kainate receptors. These neuroprotective effects required protracted treatment and were correlated with enhanced acetylated histone levels, indicating HDAC inhibition. SYM-induced excitotoxicity was blocked by MK-801 ((5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate), supporting that the toxicity was largely N-methyl-D-aspartate receptor dependent. SYM excitotoxicity had apoptotic characteristics and was prevented by a caspase inhibitor. SYM-induced apoptosis was associated with a rapid and robust nuclear accumulation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a housekeeping gene previously shown to be proapoptotic. VPA pretreatment suppressed SYM 2081-induced GAPDH nuclear accumulation, concurrent with its neuroprotective effects. Chromatin immunoprecipitation (ChIP) revealed that GAPDH is copresent with acetylated histone H3, including Lys9-acetylated histone, and that VPA treatment caused a time-dependent decrease in the levels of nuclear GAPDH with a concomitant increase in acetylated histones in the ChIP complex. Our results strongly suggest that VPA protects neurons from excitotoxicity through inhibition of HDAC activity and that this protective effect may involve suppression of excitotoxicity-induced accumulation of GAPDH protein in the nucleus.
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Affiliation(s)
- H Kanai
- Molecular Neurobiology Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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