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Tebben J, Zurhelle C, Tubaro A, Samdal IA, Krock B, Kilcoyne J, Sosa S, Trainer VL, Deeds JR, Tillmann U. Structure and toxicity of AZA-59, an azaspiracid shellfish poisoning toxin produced by Azadinium poporum (Dinophyceae). HARMFUL ALGAE 2023; 124:102388. [PMID: 37164556 DOI: 10.1016/j.hal.2023.102388] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/13/2023] [Accepted: 01/18/2023] [Indexed: 05/12/2023]
Abstract
To date, the putative shellfish toxin azaspiracid 59 (AZA-59) produced by Azadinium poporum (Dinophyceae) has been the only AZA found in isolates from the Pacific Northwest coast of the USA (Northeast Pacific Ocean). Anecdotal reports of sporadic diarrhetic shellfish poisoning-like illness, with the absence of DSP toxin or Vibrio contamination, led to efforts to look for other potential toxins, such as AZAs, in water and shellfish from the region. A. poporum was found in Puget Sound and the outer coast of Washington State, USA, and a novel AZA (putative AZA-59) was detected in low quantities in SPATT resins and shellfish. Here, an A. poporum strain from Puget Sound was mass-cultured and AZA-59 was subsequently purified and structurally characterized. In vitro cytotoxicity of AZA-59 towards Jurkat T lymphocytes and acute intraperitoneal toxicity in mice in comparison to AZA-1 allowed the derivation of a provisional toxicity equivalency factor of 0.8 for AZA-59. Quantification of AZA-59 using ELISA and LC-MS/MS yielded reasonable quantitative results when AZA-1 was used as an external reference standard. This study assesses the toxic potency of AZA-59 and will inform guidelines for its potential monitoring in case of increasing toxin levels in edible shellfish.
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Affiliation(s)
- Jan Tebben
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Section Ecological Chemistry, Am Handelshafen 12, Bremerhaven, 27570, Germany.
| | - Christian Zurhelle
- University of Bremen, Department of Biology and Chemistry, Marine Chemistry, Leobener Straße 6, Bremen, 28359, Germany
| | - Aurelia Tubaro
- Department of Life Sciences, University of Trieste, Via A. Valerio 6, Trieste, 34127, Italy
| | | | - Bernd Krock
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Section Ecological Chemistry, Am Handelshafen 12, Bremerhaven, 27570, Germany
| | - Jane Kilcoyne
- Marine Institute, Rinville, Oranmore, County Galway H91 R673, Ireland
| | - Silvio Sosa
- Department of Life Sciences, University of Trieste, Via A. Valerio 6, Trieste, 34127, Italy
| | - Vera L Trainer
- Olympic Natural Resources Center, University of Washington, 1455 S. Forks Ave, Forks, WA 98331, United States
| | - Jonathan R Deeds
- Center for Food Safety and Applied Nutrition, Office of Regulatory Science, U.S. Food and Drug Administration, 5001 Campus Drive, College Park, Maryland, 20740, United States of America
| | - Urban Tillmann
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Section Ecological Chemistry, Am Handelshafen 12, Bremerhaven, 27570, Germany.
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Boente-Juncal A, Raposo-García S, Louzao MC, Vale C, Botana LM. Targeting Chloride Ion Channels: New Insights into the Mechanism of Action of the Marine Toxin Azaspiracid. Chem Res Toxicol 2021; 34:865-879. [PMID: 33512997 DOI: 10.1021/acs.chemrestox.0c00494] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Azaspiracids (AZAs) are marine toxins produced by dinoflagellates belonging to the genera Azadinium and Amphidoma that caused human intoxications after consumption of contaminated fishery products, such as mussels. However, the exact mechanism for the AZA induced cytotoxic and neurotoxic effects is still unknown. In this study several pharmacological approaches were employed to evaluate the role of anion channels on the AZA effects that demonstrated that cellular anion dysregulation was involved in the toxic effects of these compounds. The results presented here demonstrated that volume regulated anion channels (VRACs) are affected by this group of toxins, and, because there is not any specific activator of VRACs besides the intracellular application of GTPγ-S molecule, this group of natural compounds could represent a powerful tool to analyze the role of these channels in cellular homeostasis. In addition to this, in this work, a detailed pharmacological approach was performed in order to elucidate the anion channels present in human HEK293 cells as well as their regulation by the marine toxins azaspiracids. Altogether, the data presented here demonstrated that the effect of azaspiracids in human cells was completely dependent on ATP-regulated anion channels, whose upregulation by these toxins could lead to regulatory volume decrease and underlie the reported toxicity of these compounds.
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Affiliation(s)
- Andrea Boente-Juncal
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - Sandra Raposo-García
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - M Carmen Louzao
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - Carmen Vale
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - Luis M Botana
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
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Mudge EM, Miles CO, Hardstaff WR, McCarron P. Fatty acid esters of azaspiracids identified in mussels ( Mytilus edulis) using liquid chromatography-high resolution mass spectrometry. Toxicon X 2020; 8:100059. [PMID: 33073234 PMCID: PMC7549145 DOI: 10.1016/j.toxcx.2020.100059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/25/2020] [Accepted: 09/25/2020] [Indexed: 12/02/2022] Open
Abstract
Azaspiracids (AZAs) are lipophilic polyether toxins produced by Azadinium and Amphidoma species of marine microalgae. The main dinoflagellate precursors AZA1 and AZA2 are metabolized by shellfish to produce an array of AZA analogues. Many marine toxins undergo fatty acid esterification in shellfish, therefore mussel tissues contaminated with AZAs were screened for intact fatty acid esters of AZAs using liquid chromatography-high resolution mass spectrometry. Acyl esters were primarily observed for AZAs containing hydroxy groups at C-3 with 3-O-palmitoylAZA4 identified as the most abundant acyl ester, while other fatty acid esters including 18:1, 16:1, 17:0, 20:2 and 18:0 acyl esters were detected. The structures of these acyl derivatives were determined through LC-MS/MS experiments, and supported by periodate cleavage reactions and semi-synthesis of palmitate esters of the AZAs. Esters of the hydroxy groups at C-20 or C-21 were not observed in mussel tissue. The relative proportion of the most abundant AZA ester was less than 3% of the sum of the major free AZA analogues. These findings reveal an additional metabolic pathway for AZAs in shellfish. Fatty acid esters of azaspiracids were identified in mussels (Mytilus edulis). Fatty acid esters of azaspiracids with hydroxy groups at C-3 were primarily observed. Fatty acid esters of regulated azaspiracids (AZA1, 2, −3) were absent. Structures were determined with LC-HRMS and confirmed by semi-synthesis of palmitate esters and periodate cleavage. This work reveals an additional metabolic pathway for azaspiracids in shellfish.
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Boente-Juncal A, Raposo-García S, Costas C, Louzao MC, Vale C, Botana LM. Partial Blockade of Human Voltage-Dependent Sodium Channels by the Marine Toxins Azaspiracids. Chem Res Toxicol 2020; 33:2593-2604. [DOI: 10.1021/acs.chemrestox.0c00216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Andrea Boente-Juncal
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Sandra Raposo-García
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Celia Costas
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - M. Carmen Louzao
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Carmen Vale
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Luis M. Botana
- Departamento de Farmacologı́a, Farmacia y Tecnologı́a Farmacéutica, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
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Kilcoyne J, McCarron P, Twiner MJ, Rise F, Hess P, Wilkins AL, Miles CO. Identification of 21,22-Dehydroazaspiracids in Mussels ( Mytilus edulis) and in Vitro Toxicity of Azaspiracid-26. JOURNAL OF NATURAL PRODUCTS 2018; 81:885-893. [PMID: 29488755 DOI: 10.1021/acs.jnatprod.7b00973] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Azaspiracids (AZAs) are marine biotoxins produced by the genera Azadinium and Amphidoma, pelagic marine dinoflagellates that may accumulate in shellfish resulting in human illness following consumption. The complexity of these toxins has been well documented, with more than 40 structural variants reported that are produced by dinoflagellates, result from metabolism in shellfish, or are extraction artifacts. Approximately 34 μg of a new AZA with MW 823 Da (AZA26 (3)) was isolated from blue mussels ( Mytilus edulis), and its structure determined by MS and NMR spectroscopy. AZA26, possibly a bioconversion product of AZA5, lacked the C-20-C-21 diol present in all AZAs reported thus far and had a 21,22-olefin and a keto group at C-23. Toxicological assessment of 3 using an in vitro model system based on Jurkat T lymphocyte cells showed the potency to be ∼30-fold lower than that of AZA1. The corresponding 21,22-dehydro-23-oxo-analogue of AZA10 (AZA28) and 21,22-dehydro analogues of AZA3, -4, -5, -6, -9, and -10 (AZA25, -48 (4), -60, -27, -49, and -61, respectively) were also identified by HRMS/MS, periodate cleavage reactivity, conversion from known analogues, and NMR (for 4 that was present in a partially purified sample of AZA7).
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Affiliation(s)
- Jane Kilcoyne
- Marine Institute , Rinville, Oranmore , Co. Galway H91 R673 , Ireland
| | - Pearse McCarron
- Measurement Science and Standards , National Research Council Canada , Halifax , NS B3H 3Z1 , Canada
| | - Michael J Twiner
- Department of Emergency Medicine, Detroit Receiving Hospital , Wayne State University , Detroit , Michigan 48202 , United States
| | - Frode Rise
- Department of Chemistry , University of Oslo , N-0315 Oslo , Norway
| | - Philipp Hess
- Ifremer, Laboratoire Phycotoxines , Rue de l'Ile d'Yeu , 44311 Nantes , France
| | - Alistair L Wilkins
- Norwegian Veterinary Institute , P.O. Box 750 Sentrum, 0106 Oslo , Norway
| | - Christopher O Miles
- Measurement Science and Standards , National Research Council Canada , Halifax , NS B3H 3Z1 , Canada
- Norwegian Veterinary Institute , P.O. Box 750 Sentrum, 0106 Oslo , Norway
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Tillmann U, Jaén D, Fernández L, Gottschling M, Witt M, Blanco J, Krock B. Amphidoma languida (Amphidomatacea, Dinophyceae) with a novel azaspiracid toxin profile identified as the cause of molluscan contamination at the Atlantic coast of southern Spain. HARMFUL ALGAE 2017; 62:113-126. [PMID: 28118886 DOI: 10.1016/j.hal.2016.12.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 06/06/2023]
Abstract
Azaspiracids (AZA) are a group of food poisoning phycotoxins that are known to accumulate in shellfish. They are produced by some species of the planktonic dinophycean taxon Amphidomataceae. Azaspiracids have been first discovered in Ireland but are now reported in shellfish from numerous global sites thus showing a wide distribution. In shellfish samples collected in 2009 near Huelva (Spain), AZA was also found along the Andalusian Atlantic coast for the first time. Analysis using LC-MS/MS revealed the presence of two different AZA analogues in different bivalve shellfish species (Chamelea gallina, Cerastoderma edule, Donax trunculus, and Solen vagina). In a number of samples, AZA levels exceeded the EU regulatory level of 160μg AZA-1 eq. kg-1 (reaching maximum levels of >500μg AZA-1 eq. kg-1 in Chamelea gallina and >250μg AZA-1 eq. kg-1 in Donax trunculus) causing closures of some local shellfish production areas. One dinophyte strain established from the local plankton during the AZA contamination period and determined as Amphidoma languida was in fact toxigenic, and its AZA profile disclosed it as the causative species: it contained AZA-2 as the main compound and the new compound AZA-43 initially detected in the shellfish. AZA-43 had the same mass as AZA-3, but produced different collision induced dissociation (CID) spectra. High resolution mass spectrometric measurements indicated that there is an unsaturation in the H, I ring system of AZA-43 distinguishing it from the classical AZA such as AZA-1, -2, and -3. Furthermore, the Spanish strain was different from the previously reported AZA profile of the species that consist of AZA-38 and AZ-39. In molecular phylogenetics, the Andalusian strain formed a monophyletic group together with other strains of Am. languida, but ITS sequences data revealed surprisingly high intragenomic variability. The first Andalusian case of AZA contamination of shellfish above the EU regulatory limit reported here clearly revealed the risk of azaspiracid poisoning (AZP) for this area and also for the Atlantic coast of Iberia and North Africa. The present study underlines the need for continuous monitoring of AZA and the organisms producing such toxins.
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Affiliation(s)
- Urban Tillmann
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, Germany.
| | - David Jaén
- Laboratorio de Control de Calidad de los Recursos Pesqueros, Ctra. Punta Umbría-Cartaya, km 12, 21459 Cartaya, Spain
| | - Lourdes Fernández
- Laboratorio de Control de Calidad de los Recursos Pesqueros, Ctra. Punta Umbría-Cartaya, km 12, 21459 Cartaya, Spain
| | - Marc Gottschling
- Department Biologie, Systematische Botanik und Mykologie, GeoBio-Center, Ludwig-Maximilians-Universität München, Menzinger Str. 67, D-80638 München, Germany
| | - Matthias Witt
- Bruker Daltonik GmbH, Fahrenheitstr. 4, 28359 Bremen, Germany
| | - Juan Blanco
- Centro de Investigacións Mariñas, Apdo 13. 36620 Vilanova de Arousa, Spain
| | - Bernd Krock
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, Germany
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Twiner MJ, Doucette GJ, Pang Y, Fang C, Forsyth CJ, Miles CO. Structure-Activity Relationship Studies Using Natural and Synthetic Okadaic Acid/Dinophysistoxin Toxins. Mar Drugs 2016; 14:md14110207. [PMID: 27827901 PMCID: PMC5128750 DOI: 10.3390/md14110207] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 08/07/2016] [Accepted: 10/31/2016] [Indexed: 12/25/2022] Open
Abstract
Okadaic acid (OA) and the closely related dinophysistoxins (DTXs) are algal toxins that accumulate in shellfish and are known serine/threonine protein phosphatase (ser/thr PP) inhibitors. Phosphatases are important modulators of enzyme activity and cell signaling pathways. However, the interactions between the OA/DTX toxins and phosphatases are not fully understood. This study sought to identify phosphatase targets and characterize their structure–activity relationships (SAR) with these algal toxins using a combination of phosphatase activity and cytotoxicity assays. Preliminary screening of 21 human and yeast phosphatases indicated that only three ser/thr PPs (PP2a, PP1, PP5) were inhibited by physiologically saturating concentrations of DTX2 (200 nM). SAR studies employed naturally-isolated OA, DTX1, and DTX2, which vary in degree and/or position of methylation, in addition to synthetic 2-epi-DTX2. OA/DTX analogs induced cytotoxicity and inhibited PP activity with a relatively conserved order of potency: OA = DTX1 ≥ DTX2 >> 2-epi-DTX. The PPs were also differentially inhibited with sensitivities of PP2a > PP5 > PP1. These findings demonstrate that small variations in OA/DTX toxin structures, particularly at the head region (i.e., C1/C2), result in significant changes in toxicological potency, whereas changes in methylation at C31 and C35 (tail region) only mildly affect potency. In addition to this being the first study to extensively test OA/DTX analogs’ activities towards PP5, these data will be helpful for accurately determining toxic equivalence factors (TEFs), facilitating molecular modeling efforts, and developing highly selective phosphatase inhibitors.
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Affiliation(s)
- Michael J Twiner
- School of Medicine, Wayne State University, Detroit, MI 48201, USA.
- Department of Natural Sciences, University of Michigan, Dearborn, MI 48128, USA.
| | - Gregory J Doucette
- Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, NOAA/National Ocean Service, Charleston, SC 29412, USA.
| | - Yucheng Pang
- Department of Chemistry, The Ohio State University, Columbus, OH 43220, USA.
| | - Chao Fang
- Department of Chemistry, The Ohio State University, Columbus, OH 43220, USA.
| | - Craig J Forsyth
- Department of Chemistry, The Ohio State University, Columbus, OH 43220, USA.
| | - Christopher O Miles
- Section for Chemistry and Toxicology, Norwegian Veterinary Institute, Oslo 0454, Norway.
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Doerr B, O'Halloran J, O'Brien N, van Pelt F. Investigation of the genotoxic potential of the marine biotoxins azaspiracid 1-3. Toxicon 2016; 121:61-69. [PMID: 27576062 DOI: 10.1016/j.toxicon.2016.08.019] [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: 07/05/2016] [Revised: 08/19/2016] [Accepted: 08/25/2016] [Indexed: 11/26/2022]
Abstract
Azaspiracids (AZAs) are the most recently discovered group of biotoxins and are the cause of azaspiracid shellfish poisoning (AZP) in humans. To date over thirty analogues have been identified. However, toxicological studies of AZAs are limited due to the lack of availability of toxins and toxin standards. Most data available are on acute toxicity and there are no data available on genotoxicity of AZAs. This study presents an integrated approach investigating the genotoxic potential of AZA1-3 in cell culture systems using the Comet assay combined with assays to provide information on possible apoptotic processes, cytotoxicity and changes in cell number. Results demonstrate a time and dose dependent increase in DNA fragmentation in most cell lines, indicating a genotoxic effect of AZA1-3. However, a significant reduction in cell number and a clear shift from early to late apoptosis was observed for all analogues in Jurkat T cells and HepG-2 cells; CaCo-2 cells did not show a clear apoptotic profile. Late apoptotic/necrotic cells correlate well with the percentage of tail DNA for all analogues in all three cell lines. All data taken together indicate that AZA1-3 is not genotoxic per se and demonstrate apoptotic/necrotic processes to be involved to some extent in AZAs toxicity. The sensitivities of cell lines and the different potencies of AZA1-3 are in agreement with the literature available. The order of sensitivity for all three AZAs tested in the present study is, in increasing order, CaCo-2 cells < HepG-2 cells < Jurkat T cells. The order of potency of AZA1-3 varies among the cell lines.
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Affiliation(s)
- Barbara Doerr
- Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland; Environmental Research Institute, University College Cork, Cork, Ireland.
| | - John O'Halloran
- Environmental Research Institute, University College Cork, Cork, Ireland; School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.
| | - Nora O'Brien
- School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
| | - Frank van Pelt
- Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland; Environmental Research Institute, University College Cork, Cork, Ireland.
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Krock B, Tillmann U, Potvin É, Jeong HJ, Drebing W, Kilcoyne J, Al-Jorani A, Twiner MJ, Göthel Q, Köck M. Structure Elucidation and in Vitro Toxicity of New Azaspiracids Isolated from the Marine Dinoflagellate Azadinium poporum. Mar Drugs 2015; 13:6687-702. [PMID: 26528990 PMCID: PMC4663548 DOI: 10.3390/md13116687] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/14/2015] [Accepted: 10/14/2015] [Indexed: 11/23/2022] Open
Abstract
Two strains of Azadinium poporum, one from the Korean West coast and the other from the North Sea, were mass cultured for isolation of new azaspiracids. Approximately 0.9 mg of pure AZA-36 (1) and 1.3 mg of pure AZA-37 (2) were isolated from the Korean (870 L) and North Sea (120 L) strains, respectively. The structures were determined to be 3-hydroxy-8-methyl-39-demethyl-azaspiracid-1 (1) and 3-hydroxy-7,8-dihydro-39-demethyl-azaspiracid-1 (2) by ¹H- and (13)C-NMR. Using the Jurkat T lymphocyte cell toxicity assay, (1) and (2) were found to be 6- and 3-fold less toxic than AZA-1, respectively.
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Affiliation(s)
- Bernd Krock
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, Bremerhaven 27570, Germany; E-Mails: (U.T.); (W.D.); (Q.G.)
| | - Urban Tillmann
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, Bremerhaven 27570, Germany; E-Mails: (U.T.); (W.D.); (Q.G.)
| | - Éric Potvin
- Division of Polar Ocean Environment, Korea Polar Research Institute, Incheon 406-840, Korea; E-Mail:
| | - Hae Jin Jeong
- School of Earth and Environmental Science, Seoul National University, Seoul 151-747, Korea; E-Mail:
| | - Wolfgang Drebing
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, Bremerhaven 27570, Germany; E-Mails: (U.T.); (W.D.); (Q.G.)
| | - Jane Kilcoyne
- Marine Institute, Rinville, Oranmore, Co. Galway, H91 R673, Ireland; E-Mail:
| | - Ahmed Al-Jorani
- Department of Natural Sciences, University of Michigan, Dearborn, MI 48202, USA; E-Mails: (A.A.-J.); (M.J.T.)
| | - Michael J. Twiner
- Department of Natural Sciences, University of Michigan, Dearborn, MI 48202, USA; E-Mails: (A.A.-J.); (M.J.T.)
| | - Qun Göthel
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, Bremerhaven 27570, Germany; E-Mails: (U.T.); (W.D.); (Q.G.)
| | - Matthias Köck
- Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, Bremerhaven 27570, Germany; E-Mails: (U.T.); (W.D.); (Q.G.)
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Kilcoyne J, Twiner MJ, McCarron P, Crain S, Giddings SD, Foley B, Rise F, Hess P, Wilkins AL, Miles CO. Structure Elucidation, Relative LC-MS Response and In Vitro Toxicity of Azaspiracids 7-10 Isolated from Mussels (Mytilus edulis). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:5083-5091. [PMID: 25909151 DOI: 10.1021/acs.jafc.5b01320] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Azaspiracids (AZAs) are marine biotoxins produced by dinoflagellates that can accumulate in shellfish, which if consumed can lead to poisoning events. AZA7-10, 7-10, were isolated from shellfish and their structures, previously proposed on the basis of only LC-MS/MS data, were confirmed by NMR spectroscopy. Purified AZA4-6, 4-6, and 7-10 were accurately quantitated by qNMR and used to assay cytotoxicity with Jurkat T lymphocyte cells for the first time. LC-MS(MS) molar response studies performed using isocratic and gradient elution in both selected ion monitoring and selected reaction monitoring modes showed that responses for the analogues ranged from 0.3 to 1.2 relative to AZA1, 1. All AZA analogues tested were cytotoxic to Jurkat T lymphocyte cells in a time- and concentration-dependent manner; however, there were distinct differences in their EC50 values, with the potencies for each analogue being: AZA6 > AZA8 > AZA1 > AZA4 ≈ AZA9 > AZA5 ≈ AZA10. This data contributes to the understanding of the structure-activity relationships of AZAs.
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Affiliation(s)
- Jane Kilcoyne
- †Marine Institute, Rinville, Oranmore, County Galway, Ireland
- ‡School of Chemical and Pharmaceutical Sciences, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland
| | - Michael J Twiner
- §School of Medicine, Wayne State University, Detroit, Michigan 48202, United States
| | - Pearse McCarron
- ⊥Measurement Science and Standards, Biotoxin Metrology, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada
| | - Sheila Crain
- ⊥Measurement Science and Standards, Biotoxin Metrology, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada
| | - Sabrina D Giddings
- ⊥Measurement Science and Standards, Biotoxin Metrology, National Research Council Canada, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada
| | - Barry Foley
- ‡School of Chemical and Pharmaceutical Sciences, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland
| | - Frode Rise
- ∥Department of Chemistry, University of Oslo, N-0315 Oslo, Norway
| | - Philipp Hess
- ▽Ifremer, Laboratoire Phycotoxines, Rue de l'Ile d'Yeu, 44311 Nantes, France
| | | | - Christopher O Miles
- ○Norwegian Veterinary Institute, P.O. Box 750 Sentrum, 0106 Oslo Norway
- #Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo Norway
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11
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O'Driscoll D, Škrabáková Z, James KJ. Confirmation of extensive natural distribution of azaspiracids in the tissue compartments of mussels (Mytilus edulis). Toxicon 2014; 92:123-8. [DOI: 10.1016/j.toxicon.2014.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 10/24/2022]
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12
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Kilcoyne J, Nulty C, Jauffrais T, McCarron P, Herve F, Foley B, Rise F, Crain S, Wilkins AL, Twiner MJ, Hess P, Miles CO. Isolation, structure elucidation, relative LC-MS response, and in vitro toxicity of azaspiracids from the dinoflagellate Azadinium spinosum. JOURNAL OF NATURAL PRODUCTS 2014; 77:2465-2474. [PMID: 25356854 DOI: 10.1021/np500555k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We identified three new azaspiracids (AZAs) with molecular weights of 715, 815, and 829 (AZA33 (3), AZA34 (4), and AZA35, respectively) in mussels, seawater, and Azadinium spinosum culture. Approximately 700 μg of 3 and 250 μg of 4 were isolated from a bulk culture of A. spinosum, and their structures determined by MS and NMR spectroscopy. These compounds differ significantly at the carboxyl end of the molecule from known AZA analogues and therefore provide valuable information on structure-activity relationships. Initial toxicological assessment was performed using an in vitro model system based on Jurkat T lymphocyte cytotoxicity, and the potencies of 3 and 4 were found to be 0.22- and 5.5-fold that of AZA1 (1), respectively. Thus, major changes in the carboxyl end of 1 resulted in significant changes in toxicity. In mussel extracts, 3 was detected at low levels, whereas 4 and AZA35 were detected only at extremely low levels or not at all. The structures of 3 and 4 are consistent with AZAs being biosynthetically assembled from the amino end.
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Affiliation(s)
- Jane Kilcoyne
- Marine Institute , Rinville, Oranmore, Galway, Ireland
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13
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Kilcoyne J, McCarron P, Twiner MJ, Nulty C, Crain S, Quilliam MA, Rise F, Wilkins AL, Miles CO. Epimers of azaspiracids: Isolation, structural elucidation, relative LC-MS response, and in vitro toxicity of 37-epi-azaspiracid-1. Chem Res Toxicol 2014; 27:587-600. [PMID: 24506502 DOI: 10.1021/tx400434b] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Since azaspiracid-1 (AZA1) was identified in 1998, the number of AZA analogues has increased to over 30. The development of an LC-MS method using a neutral mobile phase led to the discovery of isomers of AZA1, AZA2, and AZA3, present at ~2-16% of the parent analogues in phytoplankton and shellfish samples. Under acidic mobile phase conditions, isomers and their parents are not separated. Stability studies showed that these isomers were spontaneous epimerization products whose formation is accelerated with the application of heat. The AZA1 isomer was isolated from contaminated shellfish and identified as 37-epi-AZA1 by nuclear magnetic resonance (NMR) spectroscopy and chemical analyses. Similar analysis indicated that the isomers of AZA2 and AZA3 corresponded to 37-epi-AZA2 and 37-epi-AZA3, respectively. The 37-epimers were found to exist in equilibrium with the parent compounds in solution. 37-epi-AZA1 was quantitated by NMR, and relative molar response studies were performed to determine the potential differences in LC-MS response of AZA1 and 37-epi-AZA1. Toxicological effects were determined using Jurkat T lymphocyte cells as an in vitro cell model. Cytotoxicity experiments employing a metabolically based dye (i.e., MTS) indicated that 37-epi-AZA1 elicited a lethal response that was both concentration- and time-dependent, with EC50 values in the subnanomolar range. On the basis of EC50 comparisons, 37-epi-AZA1 was 5.1-fold more potent than AZA1. This data suggests that the presence of these epimers in seafood products should be considered in the analysis of AZAs for regulatory purposes.
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Affiliation(s)
- Jane Kilcoyne
- Marine Institute, Rinville, Oranmore, County, Galway, Ireland
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14
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Twiner MJ, Doucette GJ, Rasky A, Huang XP, Roth BL, Sanguinetti MC. Marine algal toxin azaspiracid is an open-state blocker of hERG potassium channels. Chem Res Toxicol 2012; 25:1975-84. [PMID: 22856456 DOI: 10.1021/tx300283t] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Azaspiracids (AZA) are polyether marine dinoflagellate toxins that accumulate in shellfish and represent an emerging human health risk. Although human exposure is primarily manifested by severe and protracted diarrhea, this toxin class has been shown to be highly cytotoxic, a teratogen to developing fish, and a possible carcinogen in mice. Until now, AZA's molecular target has not yet been determined. Using three independent methods (voltage clamp, channel binding assay, and thallium flux assay), we have for the first time demonstrated that AZA1, AZA2, and AZA3 each bind to and block the hERG (human ether-à-go-go related gene) potassium channel heterologously expressed in HEK-293 mammalian cells. Inhibition of K(+) current for each AZA analogue was concentration-dependent (IC(50) value range: 0.64-0.84 μM). The mechanism of hERG channel inhibition by AZA1 was investigated further in Xenopus oocytes where it was shown to be an open-state-dependent blocker and, using mutant channels, to interact with F656 but not with Y652 within the S6 transmembrane domain that forms the channel's central pore. AZA1, AZA2, and AZA3 were each shown to inhibit [(3)H]dofetilide binding to the hERG channel and thallium ion flux through the channel (IC(50) value range: 2.1-6.6 μM). AZA1 did not block the K(+) current of the closely related EAG1 channel. Collectively, these data suggest that the AZAs physically block the K(+) conductance pathway of hERG1 channels by occluding the cytoplasmic mouth of the open pore. Although the concentrations necessary to block hERG channels are relatively high, AZA-induced blockage may prove to contribute to the toxicological properties of the AZAs.
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Affiliation(s)
- Michael J Twiner
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI 48128, USA.
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15
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Twiner MJ, Hanagriff JC, Butler S, Madhkoor AK, Doucette GJ. Induction of Apoptosis Pathways in Several Cell Lines following Exposure to the Marine Algal Toxin Azaspiracid. Chem Res Toxicol 2012; 25:1493-501. [DOI: 10.1021/tx3001785] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael J. Twiner
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan
48128, United States
- Marine
Biotoxins Program, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina 29412, United
States
| | - Joshua C. Hanagriff
- Marine
Biotoxins Program, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina 29412, United
States
| | - Suzanne Butler
- Marine
Biotoxins Program, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina 29412, United
States
| | - Ahmed K. Madhkoor
- Marine
Biotoxins Program, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina 29412, United
States
| | - Gregory J. Doucette
- Marine
Biotoxins Program, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina 29412, United
States
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