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van Melis LVJ, Peerdeman AM, Huiberts EHW, van Kleef RGDM, de Groot A, Westerink RHS. Effects of acute insecticide exposure on neuronal activity in vitro in rat cortical cultures. Neurotoxicology 2024; 102:58-67. [PMID: 38599286 DOI: 10.1016/j.neuro.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/13/2024] [Accepted: 04/08/2024] [Indexed: 04/12/2024]
Abstract
Exposure to pesticides, such as carbamates, organophosphates, organochlorines and pyrethroids, has been linked to various health problems, including neurotoxicity. Although most in vivo studies use only male rodents, some studies have shown in vivo sex-specific effects after acute exposure. Since in vivo studies are costly and require a large number of animals, in vitro assays that take sex-specific effects into account are urgently needed. We therefore assessed the acute effects of exposure to different carbamates (methomyl, aldicarb and carbaryl), organophosphates (chlorpyrifos (CPF), chlorpyrifos-oxon (CPO) and 3,5,6-trichloropyridinol), organochlorines (endosulfan, dieldrin and lindane) and pyrethroids (permethrin, alpha-cypermethrin and 3-phenoxy-benzoic acid (3-PBA)) on neuronal network function in sex-separated rat primary cortical cultures using micro-electrode array (MEA) recordings. Our results indicate that exposure to the carbamate carbaryl and the organophosphates CPF and CPO decreased neuronal activity, with CPO being the most potent. Notably, (network) burst patterns differed between CPF and CPO, with CPO inducing fewer, but more intense (network) bursts. Exposure to low micromolar levels of endosulfan induced a hyperexcitation, most likely due to the antagonistic effects on GABA receptors. Interestingly, females were more sensitive to endosulfan than males. Exposure to dieldrin and lindane also increased neuronal activity, albeit less than endosulfan and without sex-specific effects. Exposure to type I pyrethroid permethrin increased neuronal activity, while exposure to type II pyrethroid alpha-cypermethrin strongly decreased neuronal activity. The increase seen after permethrin exposure was more pronounced in males than in females. Together, these results show that acute exposure to different classes of pesticides exerts differential effects on neuronal activity. Moreover, it shows that MEA recordings are suited to detect sex-specific neurotoxic effects in vitro.
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Affiliation(s)
- Lennart V J van Melis
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, TD, Utrecht NL-3508, the Netherlands
| | - Anneloes M Peerdeman
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, TD, Utrecht NL-3508, the Netherlands
| | - Eva H W Huiberts
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, TD, Utrecht NL-3508, the Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, TD, Utrecht NL-3508, the Netherlands
| | - Aart de Groot
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, TD, Utrecht NL-3508, the Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, TD, Utrecht NL-3508, the Netherlands..
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van Kleef RGDM, Embry MR, Mitchell CA, Westerink RHS. Neuroactivity screening of botanical extracts using microelectrode array (MEA) recordings. Food Chem Toxicol 2024; 184:114438. [PMID: 38191119 DOI: 10.1016/j.fct.2024.114438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/19/2023] [Accepted: 01/04/2024] [Indexed: 01/10/2024]
Abstract
Toxicity testing of botanicals is challenging because of their chemical complexity and variability. Since botanicals may affect many different modes of action involved in neuronal function, we used microelectrode array (MEA) recordings of primary rat cortical cultures to screen 16 different botanical extracts for their effects on cell viability and neuronal network function in vitro. Our results demonstrate that extract materials (50 μg/mL) derived from goldenseal, milk thistle, tripterygium, and yohimbe decrease mitochondrial activity following 7 days exposure, indicative of cytotoxicity. Importantly, most botanical extracts alter neuronal network function following acute exposure. Extract materials (50 μg/mL) derived from aristolochia, ephedra, green tea, milk thistle, tripterygium, and usnea inhibit neuronal activity. Extracts of kava, kratom and yohimbe are particularly potent and induce a profound inhibition of neuronal activity at the low dose of 5 μg/mL. Extracts of blue cohosh, goldenseal and oleander cause intensification of the bursts. Aconite extract (5 μg/mL) evokes a clear hyperexcitation with a marked increase in the number of spikes and (network) bursts. The distinct activity patterns suggest that botanical extracts have diverse modes of action. Our combined data also highlight the applicability of MEA recordings for hazard identification and potency ranking of botanicals.
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Affiliation(s)
- Regina G D M van Kleef
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands.
| | - Michelle R Embry
- Health and Environmental Sciences Institute, Washington, DC, USA.
| | | | - Remco H S Westerink
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands.
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Gerber LS, van Kleef RGDM, Fokkens P, Cassee FR, Westerink RH. In vitro neurotoxicity screening of engine oil- and hydraulic fluid-derived aircraft cabin bleed-air contamination. Neurotoxicology 2023; 96:184-196. [PMID: 37120036 DOI: 10.1016/j.neuro.2023.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/01/2023]
Abstract
In most airplanes, cabin air is extracted from the turbine compressors, so-called bleed air. Bleed air can become contaminated by leakage of engine oil or hydraulic fluid and possible neurotoxic constituents, like triphenyl phosphate (TPhP) and tributyl phosphate (TBP). The aim of this study was to characterize the neurotoxic hazard of TBP and TPhP, and to compare this with the possible hazard of fumes originating from engine oils and hydraulic fluids in vitro. Effects on spontaneous neuronal activity were recorded in rat primary cortical cultures grown on microelectrode arrays following exposure for 0.5h (acute), and 24h and 48h (prolonged) to TBP and TPhP (0.01 - 100µM) or fume extracts (1 - 100µg/mL) prepared from four selected engine oils and two hydraulic fluids by a laboratory bleed air simulator. TPhP and TBP concentration-dependently reduced neuronal activity with equal potency, particularly during acute exposure (TPhP IC50: 10 - 12µM; TBP IC50: 15 - 18µM). Engine oil-derived fume extracts persistently reduced neuronal activity. Hydraulic fluid-derived fume extracts showed a stronger inhibition during 0.5h exposure, but the degree of inhibition attenuates during 48h. Overall, fume extracts from hydraulic fluids were more potent than those from engine oils, in particular during 0.5h exposure, although the higher toxicity is unlikely to be due only to higher levels of TBP and TPhP in hydraulic fluids. Our combined data show that bleed air contaminants originating from selected engine oils or hydraulic fluids exhibit neurotoxic hazard in vitro, with fumes derived from the selected hydraulic fluids being most potent.
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Affiliation(s)
- Lora-Sophie Gerber
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Regina G D M van Kleef
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Paul Fokkens
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Flemming R Cassee
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Remco Hs Westerink
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
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Tukker AM, Vrolijk MF, van Kleef RGDM, Sijm DTHM, Westerink RHS. Mixture effects of tetrodotoxin (TTX) and drugs targeting voltage-gated sodium channels on spontaneous neuronal activity in vitro. Toxicol Lett 2023; 373:53-61. [PMID: 36375636 DOI: 10.1016/j.toxlet.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 10/19/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
Tetrodotoxin (TTX) potently inhibits TTX-sensitive voltage-gated sodium (NaV) channels in nerve and muscle cells, potentially resulting in depressed neurotransmission, paralysis and death from respiratory failure. Since a wide range of pharmaceutical drugs is known to also act on NaV channels, the use of medicines could predispose individuals to a higher susceptibility towards TTX toxicity. We therefore first assessed the inhibitory effect of selected medicines that act on TTX-sensitive (Riluzole, Chloroquine, Fluoxetine, Valproic acid, Lamotrigine, Lidocaine) and TTX-resistant (Carbamazepine, Mexiletine, Flecainide) NaV channels on spontaneous neuronal activity of rat primary cortical cultures grown on microelectrode arrays (MEA). After establishing concentration-effect curves, binary mixtures of the medicines with TTX at calculated NOEC, IC20 and IC50 values were used to determine if pharmacodynamic interactions occur between TTX and these drugs on spontaneous neuronal activity. At IC20 and IC50 values, all medicines significantly increased the inhibitory effect of TTX on spontaneous neuronal activity of rat cortical cells in vitro. Subsequent experiments using human iPSC-derived neuronal co-cultures grown on MEAs confirmed the ability of selected medicines (Carbamazepine, Flecainide, Riluzole, Lidocaine) to inhibit spontaneous neuronal activity. Despite the need for additional experiments using human iPSC-derived neuronal co-cultures, our combined data already highlight the importance of identifying and including vulnerable risk groups in the risk assessment of TTX.
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Affiliation(s)
- Anke M Tukker
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands
| | - Misha F Vrolijk
- Faculty of Health, Medicine and Life Sciences, Department of Pharmacology and Toxicology, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands
| | - Dick T H M Sijm
- Faculty of Health, Medicine and Life Sciences, Department of Pharmacology and Toxicology, Maastricht University, 6229 ER Maastricht, the Netherlands; Office for Risk Assessment and Research, Netherlands Food and Consumer Product Safety Authority (NVWA), 3540 AA Utrecht, the Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands.
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Gerber LS, van Melis LVJ, van Kleef RGDM, de Groot A, Westerink RHS. Culture of Rat Primary Cortical Cells for Microelectrode Array (MEA) Recordings to Screen for Acute and Developmental Neurotoxicity. Curr Protoc 2021; 1:e158. [PMID: 34152700 DOI: 10.1002/cpz1.158] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Neurotoxicity testing of chemicals, drug candidates, and environmental pollutants still relies on extensive in vivo studies that are very costly, time-consuming, and ethically debated due to the large number of animals typically used. Currently, rat primary cortical cultures are widely used for in vitro neurotoxicity studies, as they closely resemble the in vitro brain with respect to the diversity of cell types, their physiological functions, and the pathological processes that they undergo. Common in vitro assays for neurotoxicity screening often focus on very target-specific endpoints such as morphological, biochemical, or electrophysiological changes, and such narrow focus can hamper translation and interpretation. Microelectrode array (MEA) recordings provide a non-invasive platform for extracellular recording of electrical activity of cultured neuronal cells, thereby enabling the evaluation of changes in neuronal (network) function as a sensitive and integrated endpoint for neurotoxicity screening. Here, we describe an in vitro approach for assessing changes in neuronal network function as a measure for neurotoxicity, using rat primary cortical cultures grown on MEAs. We provide a detailed protocol for the culture of rat primary cortical cells, and describe several experimental procedures to address acute, subchronic, and chronic exposure scenarios. We additionally describe the steps for processing and analyzing MEA and cell viability data. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Isolation and culture of rat primary cortical cells on 48-well MEA plates Support Protocol 1: Pretreatment and washing of 48-well MEA plates before first use or for re-use Support Protocol 2: Coating of 48-well MEA plates with 0.1% PEI solution Basic Protocol 2: MEA measurements during acute exposure Alternate Protocol 1: MEA measurements during subchronic exposure Alternate Protocol 2: MEA measurements during chronic exposure Support Protocol 3: Determination of cell viability after MEA experiments Basic Protocol 3: MEA data processing Basic Protocol 4: Analyzing MEA experiments after acute and subchronic exposure Alternate Protocol 3: Analyzing MEA experiments after chronic exposure.
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Affiliation(s)
- Lora-Sophie Gerber
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Lennart V J van Melis
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Aart de Groot
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Koppen A, Hunault CC, van Kleef RGDM, van Velzen AG, Westerink RHS, de Vries I, de Lange DW. Estimation of the risk of local and systemic effects in infants after ingestion of low-concentrated weak acids from descaling products. Clin Toxicol (Phila) 2021; 60:71-75. [PMID: 34121559 DOI: 10.1080/15563650.2021.1933511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION The accidental ingestion of diluted household descaling products by infants is a phenomenon that poison control centers regularly encounter. Feeding infants with baby milk prepared with water from electric kettles still containing descaler is a common way of exposure. This study aimed to determine the risks related to ingestion of (diluted) descalers by infants. METHODS pH measurements were performed using acetic acid and three different commercially available electric kettle descalers. The pH of different dilutions was measured in the absence or presence of baby milk powder. In addition, an overview was made of pH values of different electric kettle descalers as given by the product information of the manufacturer. Finally, a simple pharmacokinetic (PK) model was used to predict changes in blood pH in infants after ingestion of acetic acid, which is the most commonly used descaler. RESULTS Several commercially available electric kettle descalers have a pH <2. Even after diluting such descalers up to 10 times the pH can remain low. The addition of milk powder increases the pH of descalers containing weaker acids, with a pH >1.5, while descalers with stronger acids and pH <1 show little pH increase after the addition of milk powder. Finally, a simple PBPK model for the ingestion of acetic acid predicted that the ingestion of larger amounts of acetic acid (>1000 mg) by an infant could result in relevant changes in blood pH. CONCLUSIONS Commercially available electric kettle descaling products may pose a health risk to infants in case of accidental ingestion since the pH of some of these products can be very low, even when diluted 10-times or in the presence of baby milk powder. Oral exposure of infants to the common descaler acetic acid, after accidental preparation of baby milk with cleaning vinegar, will probably not result in serious local effects, but changes in blood pH cannot be excluded when larger amounts of acetic acid are ingested.
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Affiliation(s)
- Arjen Koppen
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Claudine C Hunault
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Regina G D M van Kleef
- Toxicology Division, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, The Netherland
| | - Agnes G van Velzen
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Remco H S Westerink
- Toxicology Division, Faculty of Veterinary Medicine, Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, The Netherland
| | - Irma de Vries
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dylan W de Lange
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, Utrecht, The Netherlands
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Bauer L, Manganaro R, Zonsics B, Hurdiss DL, Zwaagstra M, Donselaar T, Welter NGE, van Kleef RGDM, Lopez ML, Bevilacqua F, Raman T, Ferla S, Bassetto M, Neyts J, Strating JRPM, Westerink RHS, Brancale A, van Kuppeveld FJM. Rational design of highly potent broad-spectrum enterovirus inhibitors targeting the nonstructural protein 2C. PLoS Biol 2020; 18:e3000904. [PMID: 33156822 PMCID: PMC7673538 DOI: 10.1371/journal.pbio.3000904] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 11/18/2020] [Accepted: 09/22/2020] [Indexed: 12/17/2022] Open
Abstract
There is a great need for antiviral drugs to treat enterovirus (EV) and rhinovirus (RV) infections, which can be severe and occasionally life-threatening. The conserved nonstructural protein 2C, which is an AAA+ ATPase, is a promising target for drug development. Here, we present a structure-activity relationship study of a previously identified compound that targets the 2C protein of EV-A71 and several EV-B species members, but not poliovirus (PV) (EV-C species). This compound is structurally related to the Food and Drug Administration (FDA)-approved drug fluoxetine—which also targets 2C—but has favorable chemical properties. We identified several compounds with increased antiviral potency and broadened activity. Four compounds showed broad-spectrum EV and RV activity and inhibited contemporary strains of emerging EVs of public health concern, including EV-A71, coxsackievirus (CV)-A24v, and EV-D68. Importantly, unlike (S)-fluoxetine, these compounds are no longer neuroactive. By raising resistant EV-A71, CV-B3, and EV-D68 variants against one of these inhibitors, we identified novel 2C resistance mutations. Reverse engineering of these mutations revealed a conserved mechanism of resistance development. Resistant viruses first acquired a mutation in, or adjacent to, the α2 helix of 2C. This mutation disrupted compound binding and provided drug resistance, but this was at the cost of viral fitness. Additional mutations at distantly localized 2C residues were then acquired to increase resistance and/or to compensate for the loss of fitness. Using computational methods to identify solvent accessible tunnels near the α2 helix in the EV-A71 and PV 2C crystal structures, a conserved binding pocket of the inhibitors is proposed. There is a great need for antiviral drugs to treat enterovirus and rhinovirus infections, which can be severe and occasionally life-threatening. This study describes novel small molecule inhibitors that target a broad spectrum of clinically relevant enterovirus species; a common mechanism of resistance development revealed the target to be a highly conserved binding pocket in the viral helicase 2C.
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Affiliation(s)
- Lisa Bauer
- Virology Section, Infectious Disease and Immunology Division, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Roberto Manganaro
- Medicinal Chemistry, School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Birgit Zonsics
- Medicinal Chemistry, School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Daniel L. Hurdiss
- Virology Section, Infectious Disease and Immunology Division, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Marleen Zwaagstra
- Virology Section, Infectious Disease and Immunology Division, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Tim Donselaar
- Virology Section, Infectious Disease and Immunology Division, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Naemi G. E. Welter
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Regina G. D. M. van Kleef
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Moira Lorenzo Lopez
- Medicinal Chemistry, School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Federica Bevilacqua
- Medicinal Chemistry, School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Thamidur Raman
- Medicinal Chemistry, School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Salvatore Ferla
- Medicinal Chemistry, School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Marcella Bassetto
- Department of Chemistry, Swansea University, Swansea, United Kingdom
| | - Johan Neyts
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Jeroen R. P. M. Strating
- Virology Section, Infectious Disease and Immunology Division, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Remco H. S. Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Andrea Brancale
- Medicinal Chemistry, School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Frank J. M. van Kuppeveld
- Virology Section, Infectious Disease and Immunology Division, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- * E-mail:
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Post Y, Puschhof J, Beumer J, Kerkkamp HM, de Bakker MAG, Slagboom J, de Barbanson B, Wevers NR, Spijkers XM, Olivier T, Kazandjian TD, Ainsworth S, Iglesias CL, van de Wetering WJ, Heinz MC, van Ineveld RL, van Kleef RGDM, Begthel H, Korving J, Bar-Ephraim YE, Getreuer W, Rios AC, Westerink RHS, Snippert HJG, van Oudenaarden A, Peters PJ, Vonk FJ, Kool J, Richardson MK, Casewell NR, Clevers H. Snake Venom Gland Organoids. Cell 2020; 180:233-247.e21. [PMID: 31978343 DOI: 10.1016/j.cell.2019.11.038] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/29/2019] [Accepted: 11/27/2019] [Indexed: 12/12/2022]
Abstract
Wnt dependency and Lgr5 expression define multiple mammalian epithelial stem cell types. Under defined growth factor conditions, such adult stem cells (ASCs) grow as 3D organoids that recapitulate essential features of the pertinent epithelium. Here, we establish long-term expanding venom gland organoids from several snake species. The newly assembled transcriptome of the Cape coral snake reveals that organoids express high levels of toxin transcripts. Single-cell RNA sequencing of both organoids and primary tissue identifies distinct venom-expressing cell types as well as proliferative cells expressing homologs of known mammalian stem cell markers. A hard-wired regional heterogeneity in the expression of individual venom components is maintained in organoid cultures. Harvested venom peptides reflect crude venom composition and display biological activity. This study extends organoid technology to reptilian tissues and describes an experimentally tractable model system representing the snake venom gland.
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Affiliation(s)
- Yorick Post
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Jens Puschhof
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Joep Beumer
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Harald M Kerkkamp
- Naturalis Biodiversity Center, 2333 CR Leiden, the Netherlands; Institute of Biology Leiden, Department of Animal Science and Health, 2333 BE Leiden, the Netherlands
| | - Merijn A G de Bakker
- Institute of Biology Leiden, Department of Animal Science and Health, 2333 BE Leiden, the Netherlands
| | - Julien Slagboom
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, 1081 LA Amsterdam, the Netherlands
| | - Buys de Barbanson
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Nienke R Wevers
- Mimetas BV, Organ-on-a-Chip Company, 2333 CH Leiden, the Netherlands; Department of Cell and Chemical Biology, Leiden University Medical Centre, Einthovenweg 20, 2333 ZC Leiden, the Netherlands
| | - Xandor M Spijkers
- Mimetas BV, Organ-on-a-Chip Company, 2333 CH Leiden, the Netherlands; Department of Translational Neuroscience, Utrecht University Medical Center, 3584 CG Utrecht, the Netherlands
| | - Thomas Olivier
- Mimetas BV, Organ-on-a-Chip Company, 2333 CH Leiden, the Netherlands
| | - Taline D Kazandjian
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Stuart Ainsworth
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Carmen Lopez Iglesias
- The Maastricht Multimodal Molecular Imaging Institute, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Willine J van de Wetering
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; The Maastricht Multimodal Molecular Imaging Institute, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Maria C Heinz
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, the Netherlands
| | - Ravian L van Ineveld
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; The Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, the Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Harry Begthel
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Jeroen Korving
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Yotam E Bar-Ephraim
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | | | - Anne C Rios
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; The Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, the Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Hugo J G Snippert
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, the Netherlands
| | - Alexander van Oudenaarden
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Peter J Peters
- The Maastricht Multimodal Molecular Imaging Institute, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Freek J Vonk
- Naturalis Biodiversity Center, 2333 CR Leiden, the Netherlands
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, 1081 LA Amsterdam, the Netherlands; Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, the Netherlands
| | - Michael K Richardson
- Institute of Biology Leiden, Department of Animal Science and Health, 2333 BE Leiden, the Netherlands
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Hans Clevers
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; The Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, the Netherlands.
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Tukker AM, Bouwman LMS, van Kleef RGDM, Hendriks HS, Legler J, Westerink RHS. Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) acutely affect human α 1β 2γ 2L GABA A receptor and spontaneous neuronal network function in vitro. Sci Rep 2020; 10:5311. [PMID: 32210279 PMCID: PMC7093421 DOI: 10.1038/s41598-020-62152-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/04/2020] [Indexed: 11/28/2022] Open
Abstract
Concerns about the neurotoxic potential of polyfluoroalkyl substances (PFAS) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) increase, although their neurotoxic mechanisms of action remain debated. Considering the importance of the GABAA receptor in neuronal function, we investigated acute effects of PFAS on this receptor and on spontaneous neuronal network activity. PFOS (Lowest Observed Effect Concentration (LOEC) 0.1 µM) and PFOA (LOEC 1 µM) inhibited the GABA-evoked current and acted as non-competitive human GABAA receptor antagonists. Network activity of rat primary cortical cultures increased following exposure to PFOS (LOEC 100 µM). However, exposure of networks of human induced pluripotent stem cell (hiPSC)-derived neurons decreased neuronal activity. The higher sensitivity of the α1β2γ2L GABAA receptor for PFAS as compared to neuronal networks suggests that PFAS have additional mechanisms of action, or that compensatory mechanisms are at play. Differences between rodent and hiPSC-derived neuronal networks highlight the importance of proper model composition. LOECs for PFAS on GABAA receptor and neuronal activity reported here are within or below the range found in blood levels of occupationally exposed humans. For PFOS, LOECs are even within the range found in human serum and plasma of the general population, suggesting a clear neurotoxic risk.
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Affiliation(s)
- Anke M Tukker
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Lianne M S Bouwman
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Juliette Legler
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands.
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Zwartsen A, Verboven AHA, van Kleef RGDM, Wijnolts FMJ, Westerink RHS, Hondebrink L. Corrigendum to "Measuring inhibition of monoamine reuptake transporters by new psychoactive substances (NPS) in real-time using a high-throughput, fluorescence-based assay" [Toxicology in Vitro (2017) 60-71]. Toxicol In Vitro 2019; 62:104631. [PMID: 31703969 DOI: 10.1016/j.tiv.2019.104631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anne Zwartsen
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, P.O. Box 85.500, NL-3508 GA Utrecht, the Netherlands; Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands
| | - Anouk H A Verboven
- Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands
| | - Fiona M J Wijnolts
- Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, the Netherlands
| | - Laura Hondebrink
- Dutch Poisons Information Center (DPIC), University Medical Center Utrecht, P.O. Box 85.500, NL-3508 GA Utrecht, the Netherlands.
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Nicolas J, Hendriksen PJM, van Kleef RGDM, de Groot A, Bovee TFH, Rietjens IMCM, Westerink RHS. Detection of marine neurotoxins in food safety testing using a multielectrode array. Mol Nutr Food Res 2014; 58:2369-78. [DOI: 10.1002/mnfr.201400479] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 09/18/2014] [Accepted: 09/24/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Jonathan Nicolas
- Division of Toxicology; Wageningen University; Wageningen The Netherlands
- RIKILT; Institute of Food Safety; Wageningen The Netherlands
| | | | - Regina G. D. M. van Kleef
- Neurotoxicology Research Group; Division of Toxicology; Institute for Risk Assessment Sciences (IRAS); Faculty of Veterinary Medicine; Utrecht University; Utrecht The Netherlands
| | - Aart de Groot
- Neurotoxicology Research Group; Division of Toxicology; Institute for Risk Assessment Sciences (IRAS); Faculty of Veterinary Medicine; Utrecht University; Utrecht The Netherlands
| | | | | | - Remco H. S. Westerink
- Neurotoxicology Research Group; Division of Toxicology; Institute for Risk Assessment Sciences (IRAS); Faculty of Veterinary Medicine; Utrecht University; Utrecht The Netherlands
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Hendriks HS, van Kleef RGDM, Westerink RHS. Modulation of human α4β2 nicotinic acetylcholine receptors by brominated and halogen-free flame retardants as a measure for in vitro neurotoxicity. Toxicol Lett 2012; 213:266-74. [PMID: 22750351 DOI: 10.1016/j.toxlet.2012.06.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/18/2012] [Accepted: 06/20/2012] [Indexed: 11/16/2022]
Abstract
Brominated flame retardants (BFRs) are abundant persistent organic pollutants with well-studied toxicity. The toxicological and ecological concern associated with BFRs argues for replacement by safer alternatives. However, the (neuro)toxic potential of alternative halogen-free flame retardants (HFFRs) is unknown. Previous research identified the nervous system as a sensitive target organ for BFRs, with modulation of excitatory nicotinic acetylcholine (nACh) receptors as one of the modes of action. Since it is essential to assess the (neuro)toxic potential of HFFRs before large scale use, we measured the effects of three BFRs and 13 HFFRs on the function of human α(4)β(2) nACh receptors, expressed in Xenopus oocytes, using the two-electrode voltage-clamp technique. The results demonstrate that some BFRs (TBBPA and to a lesser extent BDE-209) and HFFRs (TPP, Alpi, APP, MMT and to a lesser extent ATH, ATO, MHO, MPP, RDP and ZHS) act as nACh receptor antagonists. Contrary, BPS, BDP, DOPO and ZS were unable to modulate nACh receptors. Despite the lack of toxicological data on HFFRs and the need for additional studies to perform a full (neuro)toxic risk assessment, the current data on antagonistic effects on nACh receptors could be an important step in prioritizing viable HFFRs for substitution of BFRs.
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Affiliation(s)
- Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, The Netherlands
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Hendriks HS, van Kleef RGDM, van den Berg M, Westerink RHS. Multiple novel modes of action involved in the in vitro neurotoxic effects of tetrabromobisphenol-A. Toxicol Sci 2012; 128:235-46. [PMID: 22547355 DOI: 10.1093/toxsci/kfs136] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Neurotoxicological data on the widely used brominated flame retardant tetrabromobisphenol-A (TBBPA) is limited. Since recent studies indicated that inhibitory GABA(A) and excitatory α(4)β(2) nicotinic acetylcholine (nACh) receptors are sensitive targets for persistent organic pollutants, we investigated the effects of TBBPA on these receptors, expressed in Xenopus oocytes, using the two-electrode voltage-clamp technique. Our results demonstrate that TBBPA acts as full (≥ 10 μM) and partial (≥ 0.1 μM) agonist on human GABA(A) receptors, whereas it acts as antagonist (≥ 10 μM) on human α(4)β(2) nACh receptors. Next, neuronal B35 cells were used to further study the effects of TBBPA on calcium-permeable nACh receptors using single-cell fluorescent calcium imaging. These results demonstrate that TBBPA (≥ 1 μM) inhibits acetylcholine (ACh) receptors as evidenced by a reduction in the ACh-evoked increases in the intracellular calcium concentration ([Ca(2+)](i)). Additionally, TBBPA (> 1 μM) induced a strong and concentration-dependent increase in basal [Ca(2+)](i) in B35 cells. Similarly, TBBPA (> 1 μM) increases basal [Ca(2+)](i) in dopaminergic PC12 cells. This increase is also evident under calcium-free conditions, indicating it originates from intracellular calcium stores. Moreover, depolarization-evoked increases in [Ca(2+)](i) are strongly reduced by TBBPA (≥ 1 μM), indicating TBBPA-induced inhibition of voltage-gated calcium channels. Our in vitro studies thus demonstrate that TBBPA exerts several adverse effects on functional neurotransmission endpoints with effect concentrations that are only two orders of magnitude below the highest cord serum concentrations. Although epidemiological proof for adverse TBBPA effects is lacking, our data justify the quest for flame retardants with reduced neurotoxic potential.
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Affiliation(s)
- Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Utrecht University, NL-3508 TD Utrecht, The Netherlands
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Antunes Fernandes EC, Hendriks HS, van Kleef RGDM, Reniers A, Andersson PL, van den Berg M, Westerink RHS. Activation and Potentiation of Human GABAA Receptors by Non-Dioxin–Like PCBs Depends on Chlorination Pattern. Toxicol Sci 2010; 118:183-90. [DOI: 10.1093/toxsci/kfq257] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Fernandes ECA, Hendriks HS, van Kleef RGDM, van den Berg M, Westerink RHS. Potentiation of the human GABA(A) receptor as a novel mode of action of lower-chlorinated non-dioxin-like PCBs. Environ Sci Technol 2010; 44:2864-9. [PMID: 20014829 DOI: 10.1021/es902321a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
PCBs are still ubiquitous pollutants despite the ban on their industrial and commercial use. To date, risk characterization and assessment of non-dioxin-like PCBs (NDL-PCBs), especially with respect to neurotoxicity, is hampered by a lack of data. Therefore, the effects of six common NDL congeners (PCB28, 52, 101, 138, 153 and 180) on human GABA(A) receptors, expressed in Xenopus oocytes, were investigated using the two-electrode voltage-clamp technique. When coapplied with GABA (at EC(20)), PCB28 and PCB52 concentration-dependently potentiate the GABA(A) receptor-mediated ion current. Though the LOEC for both PCB28 and PCB52 is 0.3 microM, PCB28 is more potent than PCB52 (maximum potentiation at 10 muM amounting to 98.3 +/- 12.5% and 25.5 +/- 1.4%, respectively). Importantly, coapplication of PCB28 (0.3 microM) and PCB52 (10 microM) resulted in an apparently additive potentiation of the GABA(A) response, whereas coapplication of PCB28 (0.3 microM) and PCB153 (10 microM) attenuated the PCB28-induced potentiation. The present results suggest that the potentiation of human GABA(A) receptor function is specific for lower-chlorinated NDL-PCBs and that higher molecular weight PCBs may attenuate this potentiation as a result of competitive binding to human GABA(A) receptors. Nonetheless, this novel mode of action could (partly) underlie the previously recognized NDL-PCB-induced neurobehavioral alterations.
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Affiliation(s)
- Elsa C Antunes Fernandes
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, The Netherlands.
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van Kleef RGDM, Vijverberg HPM, Westerink RHS. Selective inhibition of human heteromeric alpha9alpha10 nicotinic acetylcholine receptors at a low agonist concentration by low concentrations of ototoxic organic solvents. Toxicol In Vitro 2008; 22:1568-72. [PMID: 18602458 DOI: 10.1016/j.tiv.2008.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 05/12/2008] [Accepted: 06/11/2008] [Indexed: 11/19/2022]
Abstract
Ethylbenzene and para-xylene (p-xylene), but not the chemically closely related organic solvents ortho-xylene (o-xylene) and meta-xylene (m-xylene), are known to cause ototoxicity and irreversible hearing loss, though the underlying mechanisms are still unknown. In this study, effects of ethylbenzene and of p-, o-, and m-xylene on human heteromeric alpha9alpha10 nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes were investigated using the two-electrode voltage clamp technique. ACh dose-dependently evoked an alpha9alpha10 nAChR-mediated ion current with an EC(50) of 137 microM. When ACh is applied at a low concentration (10 microM), the nAChR-mediated ion current is inhibited by a low concentration (10 microM) of ethylbenzene and p-xylene, but not by the same concentration of the non-ototoxic solvents. At a high solvent concentration (300 microM), all solvents cause inhibition of the ion currents evoked by 10 microM ACh. Ion currents evoked by a near maximum-effective concentration ACh (1mM) are inhibited by the selected organic solvents only at 300 microM. These results demonstrate that low concentrations of the known ototoxic solvents ethylbenzene and p-xylene inhibit alpha9alpha10 nAChR-mediated ion currents, whereas the structurally related, non-ototoxic solvents m-xylene and o-xylene do not, indicating that the alpha9alpha10 nAChR is a potential target for solvent-induced ototoxicity.
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Affiliation(s)
- Regina G D M van Kleef
- Cellular and Molecular Toxicology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, The Netherlands
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Dingemans MML, de Groot A, van Kleef RGDM, Bergman A, van den Berg M, Vijverberg HPM, Westerink RHS. Hydroxylation increases the neurotoxic potential of BDE-47 to affect exocytosis and calcium homeostasis in PC12 cells. Environ Health Perspect 2008; 116:637-43. [PMID: 18470311 PMCID: PMC2367675 DOI: 10.1289/ehp.11059] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Accepted: 02/01/2008] [Indexed: 05/03/2023]
Abstract
BACKGROUND Oxidative metabolism, resulting in the formation of hydroxylated polybrominated diphenyl ether (PBDE) metabolites, may enhance the neurotoxic potential of brominated flame retardants. OBJECTIVE Our objective was to investigate the effects of a hydroxylated metabolite of 2,2',4,4'-tetra-bromodiphenyl ether (BDE-47; 6-OH-BDE-47) on changes in the intracellular Ca2+ concentration ([Ca2+]i) and vesicular catecholamine release in PC12 cells. METHODS We measured vesicular catecholamine release and [Ca2+]i using amperometry and imaging of the fluorescent Ca2+-sensitive dye Fura-2, respectively. RESULTS Acute exposure of PC12 cells to 6-OH-BDE-47 (5 microM) induced vesicular catecholamine release. Catecholamine release coincided with a transient increase in [Ca2+]i, which was observed shortly after the onset of exposure to 6-OH-BDE-47 (120 microM). An additional late increase in [Ca2+]i was often observed at > or =1 microM 6-OH-BDE-47. The initial transient increase was absent in cells exposed to the parent compound BDE-47, whereas the late increase was observed only at 20 microM. Using the mitochondrial uncoupler carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) and thapsigargin to empty intracellular Ca2+ stores, we found that the initial increase originates from emptying of the endoplasmic reticulum and consequent influx of extracellular Ca2+, whereas the late increase originates primarily from mitochondria. CONCLUSION The hydroxylated metabolite 6-OH-BDE-47 is more potent in disturbing Ca2+ homeostasis and neurotransmitter release than the parent compound BDE-47. The present findings indicate that bioactivation by oxidative metabolism adds considerably to the neurotoxic potential of PBDEs. Additionally, based on the observed mechanism of action, a cumulative neurotoxic effect of PBDEs and ortho-substituted polychlorinated biphenyls on [Ca2+]i cannot be ruled out.
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Affiliation(s)
- Milou M L Dingemans
- Toxicology Division, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
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Dingemans MML, Ramakers GMJ, Gardoni F, van Kleef RGDM, Bergman A, Di Luca M, van den Berg M, Westerink RHS, Vijverberg HPM. Neonatal exposure to brominated flame retardant BDE-47 reduces long-term potentiation and postsynaptic protein levels in mouse hippocampus. Environ Health Perspect 2007; 115:865-70. [PMID: 17589592 PMCID: PMC1892123 DOI: 10.1289/ehp.9860] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 02/05/2007] [Indexed: 05/16/2023]
Abstract
BACKGROUND Increasing environmental levels of brominated flame retardants raise concern about possible adverse effects, particularly through early developmental exposure. OBJECTIVE The objective of this research was to investigate neurodevelopmental mechanisms underlying previously observed behavioral impairments observed after neonatal exposure to polybrominated diphenyl ethers (PBDEs). METHODS C57Bl/6 mice received a single oral dose of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on postnatal day (PND) 10 (i.e., during the brain growth spurt). On PND17-19, effects on synaptic plasticity, levels of postsynaptic proteins involved in long-term potentiation (LTP), and vesicular release mechanisms were studied ex vivo. We investigated possible acute in vitro effects of BDE-47 on vesicular catecholamine release and intracellular Ca(2+) in rat pheochromocytoma (PC12) cells. RESULTS Field-excitatory postsynaptic potential (f-EPSP) recordings in the hippocampal CA1 area demonstrated reduced LTP after exposure to 6.8 mg (14 micromol)/kg body weight (bw) BDE-47, whereas paired-pulse facilitation was not affected. Western blotting of proteins in the postsynaptic, triton-insoluble fraction of hippocampal tissue revealed a reduction of glutamate receptor subunits NR2B and GluR1 and autophosphorylated-active Ca(2+)/calmodulin-dependent protein kinase II (alphaCaMKII), whereas other proteins tested appeared unaffected. Amperometric recordings in chromaffin cells from mice exposed to 68 mg (140 micromol)/kg bw BDE-47 did not reveal changes in catecholamine release parameters. Modest effects on vesicular release and intracellular Ca(2+) in PC12 cells were seen following acute exposure to 20 microM BDE-47. The combined results suggest a post-synaptic mechanism in vivo. CONCLUSION Early neonatal exposure to a single high dose of BDE-47 causes a reduction of LTP together with changes in postsynaptic proteins involved in synaptic plasticity in the mouse hippocampus.
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Affiliation(s)
- Milou M L Dingemans
- Toxicology Division, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
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Smulders CJGM, Zwart R, Bermudez I, van Kleef RGDM, Groot-Kormelink PJ, Vijverberg HPM. Cholinergic drugs potentiate human nicotinic α4β2 acetylcholine receptors by a competitive mechanism. Eur J Pharmacol 2005; 509:97-108. [PMID: 15733544 DOI: 10.1016/j.ejphar.2004.12.037] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Revised: 12/22/2004] [Accepted: 12/24/2004] [Indexed: 11/29/2022]
Abstract
Effects of cholinergic drugs on human alpha4beta2 nicotinic acetylcholine receptors expressed in Xenopus oocytes have been investigated in electrophysiological and ligand binding experiments. Atropine, scopolamine, physostigmine, and tacrine combine potentiation of ion current induced by low concentrations of acetylcholine with inhibition of ion current evoked by high concentrations of acetylcholine. Rivastigmine, galanthamine, and dichlorvos cause only inhibition of ion current evoked by low concentrations of acetylcholine. Binding experiments show that the potentiating cholinergic drugs atropine, scopolamine, and physostigmine are competitive ligands of human alpha4beta2 nicotinic acetylcholine receptors. Conversely, the inhibitory cholinergic drugs galanthamine and rivastigmine are non-competitive. The non-competitive drugs are not allosteric, since they do not affect the saturation curve of the radioligand [3H]cytisine. Effects of potentiating cholinergic drugs on nicotinic acetylcholine receptors are consistent with and predicted by a model comprising competitive drug effects at two equivalent agonist recognition sites on the nicotinic acetylcholine receptor combined with non-competitive ion channel block.
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Affiliation(s)
- Chantal J G M Smulders
- Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80176, NL-3508 TD Utrecht, The Netherlands
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Smulders CJGM, Bueters TJH, Vailati S, van Kleef RGDM, Vijverberg HPM. Block of neuronal nicotinic acetylcholine receptors by organophosphate insecticides. Toxicol Sci 2004; 82:545-54. [PMID: 15342957 DOI: 10.1093/toxsci/kfh269] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chronic and acute exposure to organophosphate (OP) pesticides may lead to persistent neurological and neurobehavioral effects, which cannot be explained by acetylcholinesterase (AChE) inhibition alone. It is suggested that other brain proteins are involved. Effects of commonly used organophosphate pesticides on rat neuronal alpha4beta2 nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus laevis oocytes have been investigated using the two-electrode voltage clamp technique. Several OP pesticides, e.g., parathion-ethyl, chlorpyrifos and disulfoton, inhibited the ACh-induced ion current with potencies in the micromolar range. The potency of inhibition increased with increasing concentrations of the agonist ACh. Comparison of the potency of nAChR inhibition with the potency of AChE inhibition demonstrated that some OPs inhibit nAChRs more potently than AChE. Binding experiments on alpha4beta2 nAChRs showed that the OPs noncompetitively interact with nAChRs. The inhibitory effects on nAChRs are adequately described and explained by a sequential two-step mechanism, in which rapidly reversible OP binding to a separate binding site leads to inhibition followed by a stabilization of the blocked state or receptor desensitization. It is concluded that OPs interact directly with neuronal alpha4beta2 nAChRs to inhibit the agonist-induced response. This implicates that neuronal alpha4beta2 nAChRs are additional targets for some OP pesticides.
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Affiliation(s)
- Chantal J G M Smulders
- Institute for Risk Assessment Sciences, Utrecht University, NL-3508 TD Utrecht, The Netherlands
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