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Brown NA, Spielmann H, Bechter R, Flint OP, Freeman SJ, Jelínek RJ, Koch E, Nau H, Newall DR, Palmer AK, Renault JY, Repetto MF, Vogel R, Wiger R. Screening Chemicals for Reproductive Toxicity: The Current Alternatives. Altern Lab Anim 2020. [DOI: 10.1177/026119299502300615] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Nigel A. Brown
- MRC Experimental Embryology and Teratology Unit, St. George's Hospital Medical School, Cranmer Terrace, London SW17 ORE, UK
| | | | - Rudolf Bechter
- Sandoz Pharma Limited, Drug Safety Assessment, 4002 Basle, Switzerland
| | - Oliver P. Flint
- Bristol-Myers Squibb, Pharmaceutical Research Institute, 6000 Thompson Road, Syracuse, NY 13221, USA
| | - Stuart J. Freeman
- SmithKline Beecham Consumer Healthcare, St George's Avenue, Weybridge, Surrey KT13 ODE, UK
| | - Richard J. Jelínek
- Department of Histology and Embtyology, 3rd Medical Faculty, Charles University, Ruska 87, 100 00 Prague 10, Czech Republic
| | - Elisabeth Koch
- Sandoz Pharma Limited, Drug Safety Assessment, 4002 Basle, Switzerland
| | - Heinz Nau
- Freie University of Berlin, Institute for Toxicology and Embryopharmacology, Garystrasse 5, 1000 Berlin 33, Germany
| | - Derek R. Newall
- GlaxoWellcome Research and Development, Genetic and Reproductive Toxicology, Ware, Herts. SG12 0DP, UK
| | - Anthony K. Palmer
- Huntingdon Research Centre, Department of Toxicology, Huntingdon, Cambs. PE18 6ES, UK
| | - Jean-Yves Renault
- Rhône-Poulenc Rorer, Drug Safety NW 9, 500 Arcola Road, Collegeville, PA 19426-0107, USA
| | | | | | - Richard Wiger
- National Institute of Public Health, Department of Environmental Medicine, Geitmyrsveien 75, 0462 Oslo 4, Norway
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Ahir BK, Sanders AP, Rager JE, Fry RC. Systems biology and birth defects prevention: blockade of the glucocorticoid receptor prevents arsenic-induced birth defects. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:332-8. [PMID: 23458687 PMCID: PMC3616967 DOI: 10.1289/ehp.1205659] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 12/21/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND The biological mechanisms by which environmental metals are associated with birth defects are largely unknown. Systems biology-based approaches may help to identify key pathways that mediate metal-induced birth defects as well as potential targets for prevention. OBJECTIVES First, we applied a novel computational approach to identify a prioritized biological pathway that associates metals with birth defects. Second, in a laboratory setting, we sought to determine whether inhibition of the identified pathway prevents developmental defects. METHODS Seven environmental metals were selected for inclusion in the computational analysis: arsenic, cadmium, chromium, lead, mercury, nickel, and selenium. We used an in silico strategy to predict genes and pathways associated with both metal exposure and developmental defects. The most significant pathway was identified and tested using an in ovo whole chick embryo culture assay. We further evaluated the role of the pathway as a mediator of metal-induced toxicity using the in vitro midbrain micromass culture assay. RESULTS The glucocorticoid receptor pathway was computationally predicted to be a key mediator of multiple metal-induced birth defects. In the chick embryo model, structural malformations induced by inorganic arsenic (iAs) were prevented when signaling of the glucocorticoid receptor pathway was inhibited. Further, glucocorticoid receptor inhibition demonstrated partial to complete protection from both iAs- and cadmium-induced neurodevelopmental toxicity in vitro. CONCLUSIONS Our findings highlight a novel approach to computationally identify a targeted biological pathway for examining birth defects prevention.
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Affiliation(s)
- Bhavesh K Ahir
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Zurich MG, Stanzel S, Kopp-Schneider A, Prieto P, Honegger P. Evaluation of aggregating brain cell cultures for the detection of acute organ-specific toxicity. Toxicol In Vitro 2012; 27:1416-24. [PMID: 22954530 DOI: 10.1016/j.tiv.2012.06.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 06/11/2012] [Accepted: 06/29/2012] [Indexed: 01/05/2023]
Abstract
As part of the ACuteTox project aimed at the development of non-animal testing strategies for predicting human acute oral toxicity, aggregating brain cell cultures (AGGR) were examined for their capability to detect organ-specific toxicity. Previous multicenter evaluations of in vitro cytotoxicity showed that some 20% of the tested chemicals exhibited significantly lower in vitro toxicity as expected from in vivo toxicity data. This was supposed to be due to toxicity at supracellular (organ or system) levels. To examine the capability of AGGR to alert for potential organ-specific toxicants, concentration-response studies were carried out in AGGR for 86 chemicals, taking as endpoints the mRNA expression levels of four selected genes. The lowest observed effect concentration (LOEC) determined for each chemical was compared with the IC20 reported for the 3T3/NRU cytotoxicity assay. A LOEC lower than IC20 by at least a factor of 5 was taken to alert for organ-specific toxicity. The results showed that the frequency of alerts increased with the level of toxicity observed in AGGR. Among the chemicals identified as alert were many compounds known for their organ-specific toxicity. These findings suggest that AGGR are suitable for the detection of organ-specific toxicity and that they could, in conjunction with the 3T3/NRU cytotoxicity assay, improve the predictive capacity of in vitro toxicity testing.
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Affiliation(s)
- Marie-Gabrielle Zurich
- Department of Physiology, University of Lausanne, Rue du Bugnon 7, CH-1005 Lausanne, Switzerland.
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Monnet-Tschudi F, Hazekamp A, Perret N, Zurich MG, Mangin P, Giroud C, Honegger P. Delta-9-tetrahydrocannabinol accumulation, metabolism and cell-type-specific adverse effects in aggregating brain cell cultures. Toxicol Appl Pharmacol 2008; 228:8-16. [DOI: 10.1016/j.taap.2007.11.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 09/28/2007] [Accepted: 11/07/2007] [Indexed: 11/27/2022]
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Hewitt MJ, Mutch P, Pratten MK. Potential teratogenic effects of benomyl in rat embryos cultured in vitro. Reprod Toxicol 2005; 20:271-80. [PMID: 15907663 DOI: 10.1016/j.reprotox.2005.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 02/08/2005] [Accepted: 02/14/2005] [Indexed: 11/20/2022]
Abstract
A possible association between environmental exposure to benomyl and anophthalmia has been suggested. The aim of the present study was to investigate potential teratogenic effects of benomyl using the 9.5 day rat embryo culture method using rat and human serum. Explanted rat embryos were cultured in rat serum (n=121) or human serum (n=90) with differing concentrations of benomyl [170 nM to 13.6 microM], dissolved in ethanol (0.136%), at least five embryos per concentration being cultured. In addition, 18 embryos were cultured in both human and rat serum with the equivalent concentration of ethanol to act as a vehicle control. The cultured embryos were then measured and scored for growth and differentiation by two blinded observers. Embryotoxic effects were considered to be demonstrated by a decrease in parameters of growth such as crown rump length, yolk sac diameter and protein content, whereas embryopathic effects were considered to be those causing a decease in parameters of differentiation such as morphological score, somite number and optic development. Benomyl [> or =5 microM] produced a significant concentration dependent deterioration in morphological score, somite number and optic development. Gross toxic effects were noticed at concentrations of >12 microM in rat serum and >10microM in human serum as indicated by a significant effect on parameters measuring size (crown rump length; yolk sac diameter and protein content). This study provides evidence that benomyl is a potential developmental toxicant, affecting many parameters of differentiation, including optic development at levels below those that could be considered embryotoxic.
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Affiliation(s)
- Matthew J Hewitt
- University of Leeds, Gledhow Wing, St James's University Hospital, Department of Obstetrics and Gynaecology, Level 9, Leeds LS97TF, UK.
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Zurich MG, Honegger P, Schilter B, Costa LG, Monnet-Tschudi F. Involvement of glial cells in the neurotoxicity of parathion and chlorpyrifos. Toxicol Appl Pharmacol 2004; 201:97-104. [PMID: 15541749 DOI: 10.1016/j.taap.2004.05.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2004] [Accepted: 05/03/2004] [Indexed: 11/15/2022]
Abstract
An in vitro model, the aggregating brain cell culture of fetal rat telencephalon, has been used to investigate the influence of glial cells on the neurotoxicity of two organophosphorus pesticides (OPs), chlorpyrifos and parathion. Mixed-cell aggregate cultures were treated continuously for 10 days between DIV 5 and 15. Parathion induced astrogliosis at concentration at which MAP-2 immunostaining, found here to be more sensitive than neuron-specific enzyme activities, was not affected. In contrast, chlorpyrifos induced a comparatively weak gliotic reaction, and only at concentrations at which neurons were already affected. After similar treatments, increased neurotoxicity of parathion and chlorpyrifos was found in aggregate cultures deprived of glial cells. These results suggest that glial cells provide neuroprotection against OPs toxicity. To address the question of the difference in toxicity between parathion and chlorpyrifos, the toxic effects of their leaving groups, p-nitrophenol and trichloropyridinol, were studied in mixed-cell aggregates. General cytotoxicity was more pronounced for trichloropyridinol and both compounds had similar toxic effects on neuron-specific enzyme activities. In contrast, trichloropyridinol induced a much stronger decrease in glutamine synthetase activity, the enzymatic marker of astrocytes. Trichloropyridinol may exert a toxic effect on astrocytes, compromising their neuroprotective function, thus exacerbating the neurotoxicity of chlorpyrifos. This is in line with the suggestion that glial cells may contribute to OPs neurotoxicity, and with the view that OPs may exert their neurotoxic effects through different mechanisms.
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Affiliation(s)
- M-G Zurich
- Department of Physiology, University of Lausanne, Lausanne, Switzerland.
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Honegger P. Aggregating neural cell cultures. CURRENT PROTOCOLS IN TOXICOLOGY 2003; Chapter 12:Unit12.9. [PMID: 23045092 DOI: 10.1002/0471140856.tx1209s15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
When freshly dissociated embryonic tissues are kept under gyratory agitation, the cells aggregate to form three-dimensional spheroids in which the cells can migrate and organize themselves, attaining maximal cellular differentiation after weeks of culture. The three-dimensional architecture of the aggregates permits direct cell-to-cell interactions and the formation of a natural cell matrix, which is fundamental to the acquisition of the histotypic properties of the aggregates. This unit describes protocols for preparing forebrain cells from embryonic rodents for aggregating cultures and maintaining these cultures to the differentiated state.
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Chapter 8: Target Organ and Target System Toxicity. Altern Lab Anim 2002. [DOI: 10.1177/026119290203001s08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Eisenbrand G, Pool-Zobel B, Baker V, Balls M, Blaauboer BJ, Boobis A, Carere A, Kevekordes S, Lhuguenot JC, Pieters R, Kleiner J. Methods of in vitro toxicology. Food Chem Toxicol 2002; 40:193-236. [PMID: 11893398 DOI: 10.1016/s0278-6915(01)00118-1] [Citation(s) in RCA: 304] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In vitro methods are common and widely used for screening and ranking chemicals, and have also been taken into account sporadically for risk assessment purposes in the case of food additives. However, the range of food-associated compounds amenable to in vitro toxicology is considered much broader, comprising not only natural ingredients, including those from food preparation, but also compounds formed endogenously after exposure, permissible/authorised chemicals including additives, residues, supplements, chemicals from processing and packaging and contaminants. A major promise of in vitro systems is to obtain mechanism-derived information that is considered pivotal for adequate risk assessment. This paper critically reviews the entire process of risk assessment by in vitro toxicology, encompassing ongoing and future developments, with major emphasis on cytotoxicity, cellular responses, toxicokinetics, modelling, metabolism, cancer-related endpoints, developmental toxicity, prediction of allergenicity, and finally, development and application of biomarkers. It describes in depth the use of in vitro methods in strategies for characterising and predicting hazards to the human. Major weaknesses and strengths of these assay systems are addressed, together with some key issues concerning major research priorities to improve hazard identification and characterisation of food-associated chemicals.
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Affiliation(s)
- G Eisenbrand
- University of Kaiserslautern, Department of Chemistry Food Chemistry & Environmental Toxicology, PO Box 3049, D-67653, Kaiserslautern, Germany
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Eskes C, Honegger P, Juillerat-Jeanneret L, Monnet-Tschudi F. Microglial reaction induced by noncytotoxic methylmercury treatment leads to neuroprotection via interactions with astrocytes and IL-6 release. Glia 2002; 37:43-52. [PMID: 11746782 DOI: 10.1002/glia.10019] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Microglial cells react early to a neurotoxic insult. However, the bioactive factors and the cell-cell interactions leading to microglial activation and finally to a neuroprotective or neurodegenerative outcome remain to be elucidated. Therefore, we analyzed the microglial reaction induced by methylmercury (MeHgCl) using cell cultures of different complexity. Isolated microglia were found to be directly activated by MeHgCl (10(-10) to 10(-6) M), as indicated by process retraction, enhanced lectin staining, and cluster formation. An association of MeHgCl-induced microglial clusters with astrocytes and neurons was observed in three-dimensional cultures. Close proximity was found between the clusters of lectin-stained microglia and astrocytes immunostained for glial fibrillary acidic protein (GFAP), which may facilitate interactions between astrocytes and reactive microglia. In contrast, immunoreactivity for microtubule-associated protein (MAP-2), a neuronal marker, was absent in the vicinity of the microglial clusters. Interactions between astrocytes and microglia were studied in cocultures treated for 10 days with MeHgCl. Interleukin-6 release was increased at 10(-7) M of MeHgCl, whereas it was decreased when each of these two cell types was cultured separately. Moreover, addition of IL-6 to three-dimensional brain cell cultures treated with 3 x 10(-7) M of MeHgCl prevented the decrease in immunostaining of the neuronal markers MAP-2 and neurofilament-M. IL-6 administered to three-dimensional cultures in the absence of MeHgCl caused astrogliosis, as indicated by increased GFAP immunoreactivity. Altogether, these results show that microglial cells are directly activated by MeHgCl and that the interaction between activated microglia and astrocytes can increase local IL-6 release, which may cause astrocyte reactivity and neuroprotection.
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Affiliation(s)
- Chantra Eskes
- Institute of Physiology, University of Lausanne, Lausanne, Switzerland
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Monnet-Tschudi F, Zurich MG, Schilter B, Costa LG, Honegger P. Maturation-dependent effects of chlorpyrifos and parathion and their oxygen analogs on acetylcholinesterase and neuronal and glial markers in aggregating brain cell cultures. Toxicol Appl Pharmacol 2000; 165:175-83. [PMID: 10873710 DOI: 10.1006/taap.2000.8934] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An in vitro model, the aggregating brain cell culture of fetal rat telencephalon, has been used to study the maturation-dependent sensitivity of brain cells to two organophosphorus pesticides (OPs), chlorpyrifos and parathion, and to their oxon derivatives. Immature (DIV 5-15) or differentiated (DIV 25-35) brain cells were treated continuously for 10 days. Acetylcholinesterase (AChE) inhibitory potency for the OPs was compared to that of eserine (physostigmine), a reversible AChE inhibitor. Oxon derivatives were more potent AChE inhibitors than the parent compounds, and parathion was more potent than chlorpyrifos. No maturation-dependent differences for AChE inhibition were found for chlorpyrifos and eserine, whereas for parathion and paraoxon there was a tendency to be more effective in immature cultures, while the opposite was true for chlorpyrifos-oxon. Toxic effects, assessed by measuring protein content as an index of general cytotoxicity, and various enzyme activities as cell-type-specific neuronal and glial markers (ChAT and GAD, for cholinergic and GABAergic neurons, respectively, and GS and CNP, for astrocytes and oligodendrocytes, respectively) were only found at more than 70% of AChE inhibition. Immature compared to differentiated cholinergic neurons appeared to be more sensitive to OP treatments. The oxon derivates were found to be more toxic on neurons than the parent compounds, and chlorpyrifos was more toxic than parathion. Eserine was not neurotoxic. These results indicate that inhibition of AChE remains the most sensitive macromolecular target of OP exposure, since toxic effects were found at concentrations in which AChE was inhibited. Furthermore, the compound-specific reactions, the differential pattern of toxicity of OPs compared to eserine, and the higher sensitivity of immature brain cells suggest that the toxic effects and inhibition of AChE are unrelated.
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Schilter B, Nöldner M, Chatterjee S, Honegger P. Anticonvulsant drug toxicity in rat brain cell aggregate cultures. Toxicol In Vitro 1995; 9:381-6. [DOI: 10.1016/0887-2333(95)00027-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Bechter R. The validation and use of in vitro teratogenicity tests. ARCHIVES OF TOXICOLOGY. SUPPLEMENT. = ARCHIV FUR TOXIKOLOGIE. SUPPLEMENT 1995; 17:170-91. [PMID: 7786155 DOI: 10.1007/978-3-642-79451-3_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- R Bechter
- Drug Safety, Sandoz Pharma Ltd, Basle, Switzerland
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Honegger P, Schilter B. The Use of Serum-Free Aggregating Brain Cell Cultures in Neurotoxicology. Neurotoxicology 1995. [DOI: 10.1016/b978-012168055-8/50037-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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