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Hong EJ, Jeung EB. Assessment of Developmental Toxicants using Human Embryonic Stem Cells. Toxicol Res 2014; 29:221-7. [PMID: 24578791 PMCID: PMC3936173 DOI: 10.5487/tr.2013.29.4.221] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 12/05/2013] [Accepted: 12/12/2013] [Indexed: 01/16/2023] Open
Abstract
Embryonic stem (ES) cells have potential for use in evaluation of developmental toxicity because they are generated in large numbers and differentiate into three germ layers following formation of embryoid bodies (EBs). In earlier study, embryonic stem cell test (EST) was established for assessment of the embryotoxic potential of compounds. Using EBs indicating the onset of differentiation of mouse ES cells, many toxicologists have refined the developmental toxicity of a variety of compounds. However, due to some limitation of the EST method resulting from species-specific differences between humans and mouse, it is an incomplete approach. In this regard, we examined the effects of several developmental toxic chemicals on formation of EBs using human ES cells. Although human ES cells are fastidious in culture and differentiation, we concluded that the relevancy of our experimental method is more accurate than that of EST using mouse ES cells. These types of studies could extend our understanding of how human ES cells could be used for monitoring developmental toxicity and its relevance in relation to its differentiation progress. In addition, this concept will be used as a model system for screening for developmental toxicity of various chemicals. This article might update new information about the usage of embryonic stem cells in the context of their possible ability in the toxicological fields.
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Affiliation(s)
- Eui-Ju Hong
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea
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52
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Roth A, Singer T. The application of 3D cell models to support drug safety assessment: opportunities & challenges. Adv Drug Deliv Rev 2014; 69-70:179-89. [PMID: 24378580 DOI: 10.1016/j.addr.2013.12.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/13/2013] [Accepted: 12/17/2013] [Indexed: 12/29/2022]
Abstract
The selection of drug candidates early in development has become increasingly important to minimize the use of animals and to avoid costly failures of drugs later in development. In vitro systems to predict and assess organ toxicity have so far been of limited value due to difficulties in demonstrating in vivo-relevant toxicity at a cell culture level. To overcome the limitations of single-cell type monolayer cultures and short-lived primary cell preparations, researchers have created novel 3-dimensional culture systems which appear to more closely resemble in vivo biology. These could become a key for the pharmaceutical industry in the evaluation of drug candidates. However, the value and acceptance of those new models in standard drug safety applications have yet to be demonstrated. This review aims to provide an overview of the different approaches undertaken in the field of pre-clinical safety assessment, organ toxicity, in particular, with an emphasis on examples and technical challenges.
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Affiliation(s)
- Adrian Roth
- F. Hoffmann-La Roche Ltd., Pharma Research, 4070 Basel, Switzerland
| | - Thomas Singer
- F. Hoffmann-La Roche Ltd., Pharma Research, 4070 Basel, Switzerland
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53
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A statistical approach towards the derivation of predictive gene sets for potency ranking of chemicals in the mouse embryonic stem cell test. Toxicol Lett 2014; 225:342-9. [DOI: 10.1016/j.toxlet.2014.01.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/15/2014] [Accepted: 01/17/2014] [Indexed: 11/24/2022]
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54
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Kameoka S, Babiarz J, Kolaja K, Chiao E. A high-throughput screen for teratogens using human pluripotent stem cells. Toxicol Sci 2013; 137:76-90. [PMID: 24154490 DOI: 10.1093/toxsci/kft239] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
There is need in the pharmaceutical and chemical industries for high-throughput human cell-based assays for identifying hazardous chemicals, thereby reducing the overall reliance on animal studies for predicting the risk of toxic responses in humans. Despite instances of human-specific teratogens such as thalidomide, the use of human cell-teratogenicity assays has just started to be explored. Herein, a human pluripotent stem cell test (hPST) for identifying teratogens is described, benchmarking the in vitro findings to traditional preclinical toxicology teratogenicity studies and when available to teratogenic outcomes in humans. The hPST method employs a 3-day monolayer directed differentiation of human embryonic stem cells. The teratogenic risk of a compound is gauged by measuring the reduction in nuclear translocation of the transcription factor SOX17 in mesendodermal cells. Decreased nuclear SOX17 in the hPST model was strongly correlated with in vivo teratogenicity. Specifically, 71 drug-like compounds with known in vivo effects, including thalidomide, were examined in the hPST. A threshold of 5 μM demonstrated 94% accuracy (97% sensitivity and 92% specificity). Furthermore, 15 environmental toxicants with physicochemical properties distinct from small molecule pharmaceutical agents were examined and a similarly strong concordance with teratogenicity outcomes from in vivo studies was observed. Finally, to assess the suitability of the hPST for high-throughput screens, a small library of 300 kinase inhibitors was tested, demonstrating the hPST platform's utility for interrogating teratogenic mechanisms and drug safety prediction. Thus, the hPST assay is a robust predictor of teratogenicity and appears to be an improvement over existing in vitro models.
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Affiliation(s)
- Sei Kameoka
- Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, Nutley, New Jersey 07110
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55
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Palmer JA, Smith AM, Egnash LA, Conard KR, West PR, Burrier RE, Donley ELR, Kirchner FR. Establishment and assessment of a new human embryonic stem cell-based biomarker assay for developmental toxicity screening. ACTA ACUST UNITED AC 2013; 98:343-63. [PMID: 24123775 DOI: 10.1002/bdrb.21078] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 09/12/2013] [Indexed: 01/07/2023]
Abstract
A metabolic biomarker-based in vitro assay utilizing human embryonic stem (hES) cells was developed to identify the concentration of test compounds that perturbs cellular metabolism in a manner indicative of teratogenicity. This assay is designed to aid the early discovery-phase detection of potential human developmental toxicants. In this study, metabolomic data from hES cell culture media were used to assess potential biomarkers for development of a rapid in vitro teratogenicity assay. hES cells were treated with pharmaceuticals of known human teratogenicity at a concentration equivalent to their published human peak therapeutic plasma concentration. Two metabolite biomarkers (ornithine and cystine) were identified as indicators of developmental toxicity. A targeted exposure-based biomarker assay using these metabolites, along with a cytotoxicity endpoint, was then developed using a 9-point dose-response curve. The predictivity of the new assay was evaluated using a separate set of test compounds. To illustrate how the assay could be applied to compounds of unknown potential for developmental toxicity, an additional 10 compounds were evaluated that do not have data on human exposure during pregnancy, but have shown positive results in animal developmental toxicity studies. The new assay identified the potential developmental toxicants in the test set with 77% accuracy (57% sensitivity, 100% specificity). The assay had a high concordance (≥75%) with existing in vivo models, demonstrating that the new assay can predict the developmental toxicity potential of new compounds as part of discovery phase testing and provide a signal as to the likely outcome of required in vivo tests.
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56
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Individual and combined developmental toxicity assessment of bisphenol A and genistein using the embryonic stem cell test in vitro. Food Chem Toxicol 2013; 60:497-505. [DOI: 10.1016/j.fct.2013.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 08/01/2013] [Accepted: 08/04/2013] [Indexed: 11/23/2022]
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57
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Pelkonen O, Turpeinen M, Hakkola J, Abass K, Pasanen M, Raunio H, Vähäkangas K. Preservation, induction or incorporation of metabolism into the in vitro cellular system − Views to current opportunities and limitations. Toxicol In Vitro 2013; 27:1578-83. [DOI: 10.1016/j.tiv.2012.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 05/25/2012] [Accepted: 06/08/2012] [Indexed: 12/15/2022]
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58
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Kim JH. Validation of alternative tests for developmental and reproductive toxicology testing: an ILSI Health and Environmental Sciences Institute perspective. Methods Mol Biol 2013; 947:475-87. [PMID: 23138922 DOI: 10.1007/978-1-62703-131-8_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The current political and societal climate is driving the science of toxicology towards developing non-animal testing methodologies. Though alternative and in vitro tests have always been a mainstay for toxicological testing, technological advances in the last decade have allowed toxicologists to move rapidly towards a better understanding of the relevance of in vitro endpoints for traditional apical endpoints. Non-animal research using new technologies have illuminated toxicologists on the mechanisms of protection and adverse health outcomes. In this context, the "validation" of alternative and in vitro tests has taken on significant importance, particularly in regard to satisfying safety concerns of drugs and chemicals in a regulatory setting. The purpose of this chapter is to briefly review the impetus for the development of alternative and in vitro tests, discuss the projects underway at the ILSI Health and Environmental Sciences Institute (HESI) that are oriented towards this topic, and summarize the processes for formal validation. It should be noted that though there are validated assays and tests, these are under constant evaluation by scientific researchers as our understanding of the underlying biological processes continues to evolve.
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Affiliation(s)
- James H Kim
- ILSI Health and Environmental Sciences Institute, Washington, DC, USA.
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59
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Evaluation of an alternative in vitro test battery for detecting reproductive toxicants. Reprod Toxicol 2013; 38:53-64. [PMID: 23511061 DOI: 10.1016/j.reprotox.2013.03.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/06/2013] [Accepted: 03/09/2013] [Indexed: 01/01/2023]
Abstract
The application of alternative methods in developmental and reproductive toxicology is challenging in view of the complexity of mechanisms involved. A battery of complementary test systems may provide a better prediction of developmental and reproductive toxicity than single assays. We tested twelve compounds with varying mechanisms of toxic action in an assay battery including 24 CALUX transcriptional activation assays, mouse cardiac embryonic stem cell test, ReProGlo assay, zebrafish embryotoxicity assay, and two CYP17 and two CYP19 activity assays. The battery correctly detected 11/12 compounds tested, with one false negative occurring, which could be explained by the absence of the specific mechanism of action of this compound in the battery. Toxicokinetic modeling revealed that toxic concentrations were in the range expected from in vivo reproductive toxicity data. This study illustrates added value of combining assays that contain complementary biological processes and mechanisms, increasing predictive value of the battery over individual assays.
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60
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Abstract
The embryonic stem cell test is an animal-free alternative test method for developmental toxicity. Mouse embryonic stem cells are cultured in a hanging drop method to form embryoid bodies. These embryoid bodies, when plated on tissue culture dishes, differentiate to form contracting myocardial cell foci within 10 days. Inhibition of cardiomyocyte differentiation by test compounds serves as the end point of the assay, as monitored by counting contracting muscle foci under the microscope.
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Affiliation(s)
- Sjors H W Schulpen
- Laboratory for Health Protection Research-National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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61
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Hartung T, Luechtefeld T, Maertens A, Kleensang A. Integrated testing strategies for safety assessments. ALTEX 2013; 30:3-18. [PMID: 23338803 PMCID: PMC3800026 DOI: 10.14573/altex.2013.1.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Despite the fact that toxicology uses many stand-alone tests, a systematic combination of several information sources very often is required: Examples include: when not all possible outcomes of interest (e.g., modes of action), classes of test substances (applicability domains), or severity classes of effect are covered in a single test; when the positive test result is rare (low prevalence leading to excessive false-positive results); when the gold standard test is too costly or uses too many animals, creating a need for prioritization by screening. Similarly, tests are combined when the human predictivity of a single test is not satisfactory or when existing data and evidence from various tests will be integrated. Increasingly, kinetic information also will be integrated to make an in vivo extrapolation from in vitro data. Integrated Testing Strategies (ITS) offer the solution to these problems. ITS have been discussed for more than a decade, and some attempts have been made in test guidance for regulations. Despite their obvious potential for revamping regulatory toxicology, however, we still have little guidance on the composition, validation, and adaptation of ITS for different purposes. Similarly, Weight of Evidence and Evidence-based Toxicology approaches require different pieces of evidence and test data to be weighed and combined. ITS also represent the logical way of combining pathway-based tests, as suggested in Toxicology for the 21st Century. This paper describes the state of the art of ITS and makes suggestions as to the definition, systematic combination, and quality assurance of ITS.
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Affiliation(s)
- Thomas Hartung
- Johns Hopkins University, Bloomberg School of Public Health, CAAT, Baltimore, MD 21205, USA.
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62
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Abstract
Toxicological hazard assessment currently finds itself at a crossroads where the existing classical test paradigm is challenged by a host of innovative approaches. Animal study protocols are being enhanced for additional parameters and improved for more efficient effect assessment with reduced animal numbers. Whilst existing testing paradigms have generally proven conservative for chemical safety assessment, novel alternative in silico and in vitro approaches and assays are being introduced that begin to elucidate molecular mechanisms of toxicity. Issues such as animal welfare, alternative assay validation, endocrine disruption, and the US-NAS report on toxicity testing in the twenty-first century have provided directionality to these developments. The reductionistic nature of individual alternative assays requires that they be combined in a testing strategy in order to provide a complete picture of the toxicological profile of a compound. One of the challenges of this innovative approach is the combined interpretation of assay results in terms of toxicologically relevant effects. Computational toxicology aims at providing that integration. In order to progress, we need to follow three steps: (1) Learn from past experience in animal studies and human diseases about critical end points and pathways of toxicity. (2) Design alternative assays for essential mechanisms of toxicity. (3) Build an integrative testing strategy tailored to human hazard assessment using a battery of available alternative tests for critical end points that provides optimal in silico and in vitro filters to upgrade toxicological hazard assessment to the mechanistic level.
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Affiliation(s)
- Aldert H Piersma
- Laboratory for Health Protection Research-National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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63
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Theunissen PT, Pennings JLA, van Dartel DAM, Robinson JF, Kleinjans JCS, Piersma AH. Complementary Detection of Embryotoxic Properties of Substances in the Neural and Cardiac Embryonic Stem Cell Tests. Toxicol Sci 2012; 132:118-30. [DOI: 10.1093/toxsci/kfs333] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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64
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Hoelting L, Scheinhardt B, Bondarenko O, Schildknecht S, Kapitza M, Tanavde V, Tan B, Lee QY, Mecking S, Leist M, Kadereit S. A 3-dimensional human embryonic stem cell (hESC)-derived model to detect developmental neurotoxicity of nanoparticles. Arch Toxicol 2012. [PMID: 23203475 PMCID: PMC3604581 DOI: 10.1007/s00204-012-0984-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Nanoparticles (NPs) have been shown to accumulate in organs, cross the blood-brain barrier and placenta, and have the potential to elicit developmental neurotoxicity (DNT). Here, we developed a human embryonic stem cell (hESC)-derived 3-dimensional (3-D) in vitro model that allows for testing of potential developmental neurotoxicants. Early central nervous system PAX6(+) precursor cells were generated from hESCs and differentiated further within 3-D structures. The 3-D model was characterized for neural marker expression revealing robust differentiation toward neuronal precursor cells, and gene expression profiling suggested a predominantly forebrain-like development. Altered neural gene expression due to exposure to non-cytotoxic concentrations of the known developmental neurotoxicant, methylmercury, indicated that the 3-D model could detect DNT. To test for specific toxicity of NPs, chemically inert polyethylene NPs (PE-NPs) were chosen. They penetrated deep into the 3-D structures and impacted gene expression at non-cytotoxic concentrations. NOTCH pathway genes such as HES5 and NOTCH1 were reduced in expression, as well as downstream neuronal precursor genes such as NEUROD1 and ASCL1. FOXG1, a patterning marker, was also reduced. As loss of function of these genes results in severe nervous system impairments in mice, our data suggest that the 3-D hESC-derived model could be used to test for Nano-DNT.
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Affiliation(s)
- Lisa Hoelting
- Department of Biology, University of Konstanz, Universitaetsstrasse 10, 78457 Konstanz, Germany
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65
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Panzica-Kelly JM, Brannen KC, Ma Y, Zhang CX, Flint OP, Lehman-McKeeman LD, Augustine-Rauch KA. Establishment of a molecular embryonic stem cell developmental toxicity assay. Toxicol Sci 2012; 131:447-57. [PMID: 23042729 DOI: 10.1093/toxsci/kfs293] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mouse embryonic stem cell test (EST) is a 10-day screen for teratogenic potential developed to reduce animal use for embryotoxicity testing of chemicals (Spielmann, 2005; Spielmann et al., 1997). In this study, we used the cytotoxicity IC(50) values and transcriptional expression changes as primary endpoints in a shorter 4-day version of the EST, the molecular embryonic stem cell assay. Mouse D3 embryonic stem cells were used for cytotoxicity assessment (monolayers) or grown as embryoid bodies in low attachment plates for transcriptional profiling. Sixty-five compounds with known in vivo teratogenicity (33 teratogens and 32 nonteratogens) were evaluated to develop a model for classifying compounds with teratogenic potential. The expression of 12 developmentally regulated gene targets (nanog, fgf5, gsc, cd34, axin2, apln, chst7, lhx1, fgf8, sox17, foxa2, and cxcr4) was measured following exposure of embryoid bodies to a single compound concentration (0.1 × the cytotoxicity IC(20)) for 4 days. In the decision-tree model, compounds with IC(50) values < 22 µM were categorized as teratogens, whereas compounds in the two groups with IC(50) values between 22-200 µM and > 200 µM were categorized as teratogens if ≥ 8 and 12 genes, respectively, were deregulated by at least 10%. Forty-seven of 65 compounds of the training set were correctly identified (72% total concordance). In a test set of 12 additional compounds (5 teratogens, 7 nonteratogens), 10 were correctly classified by this approach (83% concordance). The false positive rate in the training and test sets was 24 and 0%, respectively, indicating that this assay has potential to identify teratogens.
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66
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Riebeling C, Hayess K, Peters AK, Steemans M, Spielmann H, Luch A, Seiler AEM. Assaying embryotoxicity in the test tube: current limitations of the embryonic stem cell test (EST) challenging its applicability domain. Crit Rev Toxicol 2012; 42:443-64. [PMID: 22512667 DOI: 10.3109/10408444.2012.674483] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Testing for embryotoxicity in vitro is an attractive alternative to animal experimentation. The embryonic stem cell test (EST) is such a method, and it has been formally validated by the European Centre for the Validation of Alternative Methods. A number of recent studies have underscored the potential of this method. However, the EST performed well below the 78% accuracy expected from the validation study using a new set of chemicals and pharmaceutical compounds, and also of toxicity criteria, tested to enlarge the database of the validated EST as part of the Work Package III of the ReProTect Project funded within the 6th Framework Programme of the European Union. To assess the performance and applicability domain of the EST we present a detailed review of the substances and their effects in the EST being nitrofen, ochratoxin A, D-penicillamine, methylazoxymethanol, lovastatin, papaverine, warfarin, β-aminopropionitrile, dinoseb, furosemide, doxylamine, pravastatin, and metoclopramide. By delineation of the molecular mechanisms of the substances we identify six categories of reasons for misclassifications. Some of these limitations might also affect other in vitro methods assessing embryotoxicity. Substances that fall into these categories need to be included in future validation sets and in validation guidelines for embryotoxicity testing. Most importantly, we suggest conceivable improvements and additions to the EST which will resolve most of the limitations.
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Affiliation(s)
- Christian Riebeling
- German Federal Institute for Risk Assessment (BfR), ZEBET - Alternative Methods to Animal Experiments, Berlin, Germany
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67
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Strikwold M, Woutersen RA, Spenkelink B, Punt A, Rietjens IMCM. Relative embryotoxic potency of p-substituted phenols in the embryonic stem cell test (EST) and comparison to their toxic potency in vivo and in the whole embryo culture (WEC) assay. Toxicol Lett 2012; 213:235-42. [PMID: 22820428 DOI: 10.1016/j.toxlet.2012.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 07/09/2012] [Accepted: 07/09/2012] [Indexed: 10/28/2022]
Abstract
The applicability of the embryonic stem cell test (EST) as an alternative for in vivo embryotoxicity testing was evaluated for a series of five p-substituted phenols. To this purpose, the potency ranking for this class of compounds derived from the inhibition of cardiomyocyte differentiation in the EST was compared to in vivo embryotoxic potency data obtained from literature and to the potency ranking defined in the in vitro whole embryo culture (WEC) assay. From the results obtained it appears that the EST was able to identify the embryotoxic potential for p-substituted phenols, providing an identical potency ranking compared to the WEC assay. However, the EST was not able to predict an accurate ranking for the phenols compared to their potency observed in vivo. Only phenol, the least potent compound within this series, was correctly ranked. Furthermore, p-mercaptophenol was correctly identified as a relative potent congener of the phenols tested, but its ranking was distorted by p-heptyloxyphenol, of which the toxicity was overestimated in the EST. It is concluded that when attempting to explain the observed disparity in potency rankings between in vitro and in vivo embryotoxicity, the in vitro models should be combined with a kinetic model describing in vivo absorption, distribution, metabolism and excretion processes of the compounds.
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Affiliation(s)
- Marije Strikwold
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703 HE Wageningen, The Netherlands.
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68
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Kramer J, Bartsch M, Krug D, Klinger M, Nitschke M, Rohwedel J. Simvastatin modulates mouse embryonic stem cell-derived chondrogenesis in vitro. Toxicol In Vitro 2012; 26:1170-6. [PMID: 22771337 DOI: 10.1016/j.tiv.2012.06.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 06/22/2012] [Accepted: 06/25/2012] [Indexed: 10/28/2022]
Abstract
It has been studied in detail that cellular differentiation during chondrogenesis can be recapitulated in vitro by differentiation of embryonic stem (ES) cells as embryoid bodies (EBs). We here used this model system of cartilage development to analyze the effect of simvastatin, a potentially embryotoxic substance. Statins are a group of drugs used to treat hypercholesterolaemia. We found that simvastatin activated cartilage nodule formation during EB differentiation. Extended application of simvastatin resulted in enhanced expression of cartilage marker molecules and prolonged persistence of cartilage nodules. Expression of collagen type II was upregulated during simvastatin-induced chondrogenic ES cell differentiation as demonstrated by quantitative real time PCR. However, immunostaining for cartilage marker molecules revealed that cartilage nodules within simvastatin-treated EBs were defective, bearing cavities of cell loss. Furthermore, caspase activity was reduced in comparison to untreated controls indicating reduced apoptosis. Taken together, we may speculate that simvastatin prolongs survival of chondrocytes and disrupts cellular integrity of cartilage nodules during EB development by affecting apoptotic mechanisms. The study underlines that ES cell-derived EBs are a useful in vitro model to screen substances for their embryotoxic and teratogenic potential.
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Affiliation(s)
- J Kramer
- Medical Dept. I and Dept. of Virology and Cell Biology, University of Lübeck, 23538 Lübeck, Germany.
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69
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de Jong E, van Beek L, Piersma AH. Osteoblast differentiation of murine embryonic stem cells as a model to study the embryotoxic effect of compounds. Toxicol In Vitro 2012; 26:970-8. [PMID: 22683932 DOI: 10.1016/j.tiv.2012.05.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 05/18/2012] [Accepted: 05/29/2012] [Indexed: 12/23/2022]
Abstract
The embryonic stem cell test (ESTc), in which the effect of chemical compounds on cardiomyocyte differentiation is evaluated, is one of the most studied in vitro alternatives for developmental toxicity testing. Because the assay readout is restricted to a single endpoint of differentiation, compounds that affect alternative differentiation pathways might be overlooked. It has therefore been suggested that the predictive value of the EST may be improved by including alternative differentiation endpoints. The aim of the present study was to evaluate the effect of five teratogenic compounds as well as one non-teratogenic compound on the differentiation of murine embryonic stem cells into osteoblasts (ESTo) and to compare results with those in the classical ESTc. We established an ESTo assay which proved robust, stable and reproducible. In this study, we showed that the evaluated compounds affected osteoblast differentiation both at the level of calcium concentrations in the culture as well as on multiple gene expression. Furthermore, we showed that the effect on calcium concentrations appeared to be primarily mediated by a general apoptotic effect and not by a specific effect on differentiation. The compounds tested showed little difference in their potency in the ESTo as compared to the ESTc. Before a definitive statement can be made regarding the added value of including an osteoblast differentiation endpoint into the EST, more compounds need to be evaluated.
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Affiliation(s)
- Esther de Jong
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
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70
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Leist M, Hasiwa N, Daneshian M, Hartung T. Validation and quality control of replacement alternatives – current status and future challenges. Toxicol Res (Camb) 2012. [DOI: 10.1039/c2tx20011b] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract
Alternatives to animal testing have been developed mainly in the fields of toxicology and vaccine testing. Typical examples are the evaluation of phototoxicity, eye irritation or skin corrosion/irritation of cosmetics and industrial chemicals. However, examples can also be found in other biomedical areas, such the control of the quality of drug preparations for pyrogens or for the control of the production process of biologics, such as botulinum neurotoxin. For regulatory purposes, the quality, transferability and predictivity of an alternative method needs to be evaluated. This procedure is called the “validation process” of a new method. It follows defined rules, and several governmental institutions have been established to perform, supervise or advise on this process. As this often results in a delay of method implementation, different alternatives for the evaluation of a method's suitability and quality are under discussion. We describe here the principles of model development and quality control. We also give an overview on methods that have undergone validation. Strengths and shortcomings of traditional approaches are discussed, and new developments and challenges are outlined.
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Affiliation(s)
- Marcel Leist
- Doerenkamp-Zbinden Chair for In-vitro Toxicology and Biomedicine and Center for Alternatives to Animal Testing in Europe (CAAT-Europe), University of Konstanz, D-78467 Konstanz, Germany
| | - Nina Hasiwa
- Doerenkamp-Zbinden Chair for In-vitro Toxicology and Biomedicine and Center for Alternatives to Animal Testing in Europe (CAAT-Europe), University of Konstanz, D-78467 Konstanz, Germany
| | - Mardas Daneshian
- Doerenkamp-Zbinden Chair for In-vitro Toxicology and Biomedicine and Center for Alternatives to Animal Testing in Europe (CAAT-Europe), University of Konstanz, D-78467 Konstanz, Germany
| | - Thomas Hartung
- Doerenkamp-Zbinden Chair for In-vitro Toxicology and Biomedicine and Center for Alternatives to Animal Testing in Europe (CAAT-Europe), University of Konstanz, D-78467 Konstanz, Germany
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71
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Theunissen PT, Robinson JF, Pennings JLA, van Herwijnen MH, Kleinjans JCS, Piersma AH. Compound-specific effects of diverse neurodevelopmental toxicants on global gene expression in the neural embryonic stem cell test (ESTn). Toxicol Appl Pharmacol 2012; 262:330-40. [PMID: 22634333 DOI: 10.1016/j.taap.2012.05.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/24/2012] [Accepted: 05/11/2012] [Indexed: 10/28/2022]
Abstract
Alternative assays for developmental toxicity testing are needed to reduce animal use in regulatory toxicology. The in vitro murine neural embryonic stem cell test (ESTn) was designed as an alternative for neurodevelopmental toxicity testing. The integration of toxicogenomic-based approaches may further increase predictivity as well as provide insight into underlying mechanisms of developmental toxicity. In the present study, we investigated concentration-dependent effects of six mechanistically diverse compounds, acetaldehyde (ACE), carbamazepine (CBZ), flusilazole (FLU), monoethylhexyl phthalate (MEHP), penicillin G (PENG) and phenytoin (PHE), on the transcriptome and neural differentiation in the ESTn. All compounds with the exception of PENG altered ESTn morphology (cytotoxicity and neural differentiation) in a concentration-dependent manner. Compound induced gene expression changes and corresponding enriched gene ontology biological processes (GO-BP) were identified after 24h exposure at equipotent differentiation-inhibiting concentrations of the compounds. Both compound-specific and common gene expression changes were observed between subsets of tested compounds, in terms of significance, magnitude of regulation and functionality. For example, ACE, CBZ and FLU induced robust changes in number of significantly altered genes (≥ 687 genes) as well as a variety of GO-BP, as compared to MEHP, PHE and PENG (≤ 55 genes with no significant changes in GO-BP observed). Genes associated with developmentally related processes (embryonic morphogenesis, neuron differentiation, and Wnt signaling) showed diverse regulation after exposure to ACE, CBZ and FLU. In addition, gene expression and GO-BP enrichment showed concentration dependence, allowing discrimination of non-toxic versus toxic concentrations on the basis of transcriptomics. This information may be used to define adaptive versus toxic responses at the transcriptome level.
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Affiliation(s)
- P T Theunissen
- Laboratory for Health Protection Research, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands.
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72
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Abstract
In light of various pressures, toxicologists have been searching for alternative methods for safety testing of chemicals. According to a recent policy in the European Union (Regulation, Evaluation Authorisation and Restriction of Chemicals, REACH), it has been estimated that over the next twelve to fifteen years, approximately 30,000 chemicals may need to be tested for safety, and under current guidelines such testing would require the use of approximately 7.2 million laboratory animals [ Hofer et al. 2004 ]. It has also been estimated that over 80% of all animals used for safety testing under REACH legislation would be used for examining reproductive and developmental toxicity [Hofer et al., 2004]. In addition to REACH initiatives, it has been estimated that out of 5,000 to 10,000 new drug entities that a pharmaceutical company may start with, only one is finally approved by the Food and Drug Administration at a cost of over one billion dollars [ Garg et al. 2011 ]. A large portion of this cost is due to animal testing. Therefore, both the pharmaceutical and chemical industries are interested in using alternative models and in vitro tests for safety testing. This review will examine the current state of three alternative models - whole embryo culture (WEC), the mouse embryonic stem cell test (mEST), and zebrafish. Each of these alternatives will be reviewed, and advantages and disadvantages of each model will be discussed. These models were chosen because they are the models most commonly used and would appear to have the greatest potential for future applications in developmental toxicity screening and testing.
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Affiliation(s)
- Hyung-yul Lee
- Division of Personalized Nutrition and Medicine, FDA/National Center for Toxicological Research, Jefferson, AR 72079, USA
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73
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Ouedraogo M, Baudoux T, Stévigny C, Nortier J, Colet JM, Efferth T, Qu F, Zhou J, Chan K, Shaw D, Pelkonen O, Duez P. Review of current and "omics" methods for assessing the toxicity (genotoxicity, teratogenicity and nephrotoxicity) of herbal medicines and mushrooms. JOURNAL OF ETHNOPHARMACOLOGY 2012; 140:492-512. [PMID: 22386524 DOI: 10.1016/j.jep.2012.01.059] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 01/31/2012] [Accepted: 01/31/2012] [Indexed: 05/31/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The increasing use of traditional herbal medicines around the world requires more scientific evidence for their putative harmlessness. To this end, a plethora of methods exist, more or less satisfying. In this post-genome era, recent reviews are however scarce, not only on the use of new "omics" methods (transcriptomics, proteomics, metabonomics) for genotoxicity, teratogenicity, and nephrotoxicity assessment, but also on conventional ones. METHODS The present work aims (i) to review conventional methods used to assess genotoxicity, teratogenicity and nephrotoxicity of medicinal plants and mushrooms; (ii) to report recent progress in the use of "omics" technologies in this field; (iii) to underline advantages and limitations of promising methods; and lastly (iv) to suggest ways whereby the genotoxicity, teratogenicity, and nephrotoxicity assessment of traditional herbal medicines could be more predictive. RESULTS Literature and safety reports show that structural alerts, in silico and classical in vitro and in vivo predictive methods are often used. The current trend to develop "omics" technologies to assess genotoxicity, teratogenicity and nephrotoxicity is promising but most often relies on methods that are still not standardized and validated. CONCLUSION Hence, it is critical that toxicologists in industry, regulatory agencies and academic institutions develop a consensus, based on rigorous methods, about the reliability and interpretation of endpoints. It will also be important to regulate the integration of conventional methods for toxicity assessments with new "omics" technologies.
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Affiliation(s)
- Moustapha Ouedraogo
- Laboratory of Pharmacology and Toxicology, Health Sciences Faculty, University of Ouagadougou, 03 BP 7021 Ouagadougou 03, Burkina Faso. mustapha
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74
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Suzuki N, Ando S, Sumida K, Horie N, Saito K. Analysis of altered gene expression specific to embryotoxic chemical treatment during embryonic stem cell differentiation into myocardiac and neural cells. J Toxicol Sci 2012; 36:569-85. [PMID: 22008533 DOI: 10.2131/jts.36.569] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Embryonic stem cells (ES cells), pluripotent cells derived from the inner cell mass of blastocysts, differentiate in vitro into a variety of cell types representing all three germ layers. They therefore constitute one of the most promising in vitro tools for developmental toxicology. To assess the developmental toxicity of chemicals using ES cells easily, identification of effective marker genes is a high priority. We report here altered gene expression during ES cell differentiation into myocardiac and neural cells on treatment with some embryotoxic and non-embryotoxic chemicals. Decreases in several undifferentiated markers such as Oct3/4 and Nanog, and elevated expression of genes associated with heart development or the central nervous system, respectively, were found on microarray analysis. Under differentiation of ES cells into myocardic cells, 107 genes were substantially up-regulated. Decrease in the expression of 13 genes of these (Hand1, Pim2, Tbx20, Myl4, Myl7, Hbb-bh1, Hba-a1, Col1a2, Hba-x, Cmya1, Pitx2, Smyd1 and Adam19) was observed specifically by embryotoxic chemicals. Of the 107 genes up-regulated under differentiation into neurons, 22 genes (Map2, Cpe, Marcks, Ptbp2, Sox11, Tubb2b, Vim, Arx, Emx2, Pax6, Basp1, Ddr1, Ndn, Sfrp, Ttc3, Ubqln2, Six3, Dcx, L1cam, Reln, Wnt1 and Nnat) showed reduced expression specifically by embryotoxic chemicals. Almost all gene sets identified in this study are known to be indispensable for differentiation and development of heart and brain tissues, and thus may serve in early detection or prediction of embryotoxicity of chemicals in vitro.
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Affiliation(s)
- Noriyuki Suzuki
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., Osaka, Japan.
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75
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Testing strategies for embryo-fetal toxicity of human pharmaceuticals. Animal models vs. in vitro approaches: a workshop report. Regul Toxicol Pharmacol 2012; 63:115-23. [PMID: 22449444 DOI: 10.1016/j.yrtph.2012.03.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 03/09/2012] [Indexed: 10/28/2022]
Abstract
Reproductive toxicity testing is characterized by high animal use. For registration of pharmaceutical compounds, developmental toxicity studies are usually conducted in both rat and rabbits. Efforts have been underway for a long time to design alternatives to animal use. Implementation has lagged, partly because of uncertainties about the applicability domain of the alternatives. The reproductive cycle is complex and not all mechanisms of development can be mimicked in vitro. Therefore, efforts are underway to characterize the available alternative tests with regard to the mechanism of action they include. One alternative test is the mouse embryonic stem cell test (EST), which has been studied since the late 1990s. It is a genuine 3R "alternative" assay as it is essentially animal-free. A meeting was held to review the state-of-the-art of various in vitro models for prediction of developmental toxicity. Although the predictivity of individual assays is improving, a battery of several assays is likely to have even higher predictivity, which is necessary for regulatory acceptance. The workshop concluded that an important first step is a thorough survey of the existing rat and rabbit studies, to fully characterize the frequency of responses and the types of effects seen. At the same time, it is important to continue the optimization of in vitro assays. As more experience accumulates, the optimal conditions, assay structure, and applicability of the alternative assays are expected to emerge.
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76
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Robinson JF, Verhoef A, Pennings JLA, Pronk TE, Piersma AH. A comparison of gene expression responses in rat whole embryo culture and in vivo: time-dependent retinoic acid-induced teratogenic response. Toxicol Sci 2012; 126:242-54. [PMID: 22262565 DOI: 10.1093/toxsci/kfr342] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The whole embryo culture (WEC) model serves as a potential alternative for classical in vivo developmental toxicity testing. In the WEC, cultured rat embryos are exposed during neurulation and early organogenesis and evaluated for morphological effects. Toxicogenomic-based approaches may improve the predictive ability of WEC by providing molecular-based markers associated with chemical exposure, which can be compared across multiple parameters (e.g., exposure duration, developmental time, experimental model). Additionally, comparisons between in vitro and in vivo models may identify objective relevant molecular responses linked with developmental toxicity endpoints in vivo. In this study, using a transcriptomic approach, we compared all-trans retinoic acid (RA)-exposed and nonexposed Wistar rat embryos derived using WEC (RA, 0.5 μg/ml) or in vivo (RA, 50 mg/kg, oral gavage) to identify overlapping and nonoverlapping effects of RA on RNA expression in parallel with morphological changes. Across six time points (gestational day 10 + 2-48 h), we observed strong similarities in RA response at the gene (directionality, significance) and functional (e.g., embryonic development, cell differentiation) level which associated with RA-induced adverse morphological effects, including growth reduction as well as alterations in neural tube, limb, branchial, and mandible development. We observed differences between models in the timing of RA-induced effects on genes related to embryonic development and RA metabolism. These observations on the gene expression level were associated with specific differential morphological outcomes. This study supports the use of WEC to examine compound-induced molecular responses relative to in vivo and, furthermore, assists in defining the applicability domain of the WEC in determining complementary windows of sensitivity for developmental toxicological investigations.
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Affiliation(s)
- Joshua F Robinson
- Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
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77
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Sison-Young RLC, Kia R, Heslop J, Kelly L, Rowe C, Cross MJ, Kitteringham NR, Hanley N, Park BK, Goldring CEP. Human pluripotent stem cells for modeling toxicity. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2012; 63:207-256. [PMID: 22776643 DOI: 10.1016/b978-0-12-398339-8.00006-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The development of xenobiotics, driven by the demand for therapeutic, domestic and industrial uses continues to grow. However, along with this increasing demand is the risk of xenobiotic-induced toxicity. Currently, safety screening of xenobiotics uses a plethora of animal and in vitro model systems which have over the decades proven useful during compound development and for application in mechanistic studies of xenobiotic-induced toxicity. However, these assessments have proven to be animal-intensive and costly. More importantly, the prevalence of xenobiotic-induced toxicity is still significantly high, causing patient morbidity and mortality, and a costly impediment during drug development. This suggests that the current models for drug safety screening are not reliable in toxicity prediction, and the results not easily translatable to the clinic due to insensitive assays that do not recapitulate fully the complex phenotype of a functional cell type in vivo. Recent advances in the field of stem cell research have potentially allowed for a readily available source of metabolically competent cells for toxicity studies, derived using human pluripotent stem cells harnessed from embryos or reprogrammed from mature somatic cells. Pluripotent stem cell-derived cell types also allow for potential disease modeling in vitro for the purposes of drug toxicology and safety pharmacology, making this model possibly more predictive of drug toxicity compared with existing models. This article will review the advances and challenges of using human pluripotent stem cells for modeling metabolism and toxicity, and offer some perspectives as to where its future may lie.
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Affiliation(s)
- R L C Sison-Young
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
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78
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Bouvier d'Yvoire M, Bremer S, Casati S, Ceridono M, Coecke S, Corvi R, Eskes C, Gribaldo L, Griesinger C, Knaut H, Linge JP, Roi A, Zuang V. ECVAM and new technologies for toxicity testing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 745:154-80. [PMID: 22437818 DOI: 10.1007/978-1-4614-3055-1_10] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The development of alternative empirical (testing) and non-empirical (non-testing) methods to traditional toxicological tests for complex human health effects is a tremendous task. Toxicants may potentially interfere with a vast number of physiological mechanisms thereby causing disturbances on various levels of complexity of human physiology. Only a limited number of mechanisms relevant for toxicity ('pathways' of toxicity) have been identified with certainty so far and, presumably, many more mechanisms by which toxicants cause adverse effects remain to be identified. Recapitulating in empirical model systems (i.e., in vitro test systems) all those relevant physiological mechanisms prone to be disturbed by toxicants and relevant for causing the toxicity effect in question poses an enormous challenge. First, the mechanism(s) of action of toxicants in relation to the most relevant adverse effects of a specific human health endpoint need to be identified. Subsequently, these mechanisms need to be modeled in reductionist test systems that allow assessing whether an unknown substance may operate via a specific (array of) mechanism(s). Ideally, such test systems should be relevant for the species of interest, i.e., based on human cells or modeling mechanisms present in humans. Since much of our understanding about toxicity mechanisms is based on studies using animal model systems (i.e., experimental animals or animal-derived cells), designing test systems that model mechanisms relevant for the human situation may be limited by the lack of relevant information from basic research. New technologies from molecular biology and cell biology, as well as progress in tissue engineering, imaging techniques and automated testing platforms hold the promise to alleviate some of the traditional difficulties associated with improving toxicity testing for complex endpoints. Such new technologies are expected (1) to accelerate the identification of toxicity pathways with human relevance that need to be modeled in test methods for toxicity testing (2) to enable the reconstruction of reductionist test systems modeling at a reduced level of complexity the target system/organ of interest (e.g., through tissue engineering, use of human-derived cell lines and stem cells etc.), (3) to allow the measurement of specific mechanisms relevant for a given health endpoint in such test methods (e.g., through gene and protein expression, changes in metabolites, receptor activation, changes in neural activity etc.), (4) to allow to measure toxicity mechanisms at higher throughput rates through the use of automated testing. In this chapter, we discuss the potential impact of new technologies on the development, optimization and use of empirical testing methods, grouped according to important toxicological endpoints. We highlight, from an ECVAM perspective, the areas of topical toxicity, skin absorption, reproductive and developmental toxicity, carcinogenicity/genotoxicity, sensitization, hematopoeisis and toxicokinetics and discuss strategic developments including ECVAM's database service on alternative methods. Neither the areas of toxicity discussed nor the highlighted new technologies represent comprehensive listings which would be an impossible endeavor in the context of a book chapter. However, we feel that these areas are of utmost importance and we predict that new technologies are likely to contribute significantly to test development in these fields. We summarize which new technologies are expected to contribute to the development of new alternative testing methods over the next few years and point out current and planned ECVAM projects for each of these areas.
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79
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Louisse J, Verwei M, Woutersen RA, Blaauboer BJ, Rietjens IMCM. Towardin vitrobiomarkers for developmental toxicity and their extrapolation to thein vivosituation. Expert Opin Drug Metab Toxicol 2011; 8:11-27. [DOI: 10.1517/17425255.2012.639762] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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80
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Theunissen PT, Robinson JF, Pennings JLA, de Jong E, Claessen SMH, Kleinjans JCS, Piersma AH. Transcriptomic concentration-response evaluation of valproic acid, cyproconazole, and hexaconazole in the neural embryonic stem cell test (ESTn). Toxicol Sci 2011; 125:430-8. [PMID: 22045034 DOI: 10.1093/toxsci/kfr293] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Alternative developmental toxicity assays are urgently needed to reduce animal use in regulatory developmental toxicology. We previously designed an in vitro murine neural embryonic stem cell test (ESTn) as a model for neurodevelopmental toxicity testing (Theunissen et al., 2010). Toxicogenomic approaches have been suggested for incorporation into the ESTn to further increase predictivity and to provide mechanistic insights. Therefore, in this study, using a transcriptomic approach, we investigated the concentration-dependent effects of three known (neuro) developmental toxicants, two triazoles, cyproconazole (CYP) and hexaconazole (HEX), and the anticonvulsant valproic acid (VPA). Compound effects on gene expression during neural differentiation and corresponding regulated gene ontology (GO) terms were identified after 24 h of exposure in relation to morphological changes on day 11 of culture. Concentration-dependent responses on individual gene expression and on biological processes were determined for each compound, providing information on mechanism and concentration-response characteristics. All compounds caused enrichment of the embryonic development process. CYP and VPA but not HEX significantly enriched the neuron development process. Furthermore, specific responses for triazole compounds and VPA were observed within the GO-term sterol metabolic process. The incorporation of transcriptomics in the ESTn was shown to enable detection of effects, which precede morphological changes and provide a more sensitive measure of concentration-dependent effects as compared with classical morphological assessments. Furthermore, mechanistic insight can be instrumental in the extrapolation of effects in the ESTn to human hazard assessment.
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Affiliation(s)
- Peter T Theunissen
- Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands.
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81
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Developmental toxicity testing in the 21st century: the sword of Damocles shattered by embryonic stem cell assays? Arch Toxicol 2011; 85:1361-72. [DOI: 10.1007/s00204-011-0767-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 10/06/2011] [Indexed: 01/31/2023]
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82
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Punt A, Schiffelers MJWA, Jean Horbach G, van de Sandt JJM, Groothuis GMM, Rietjens IMCM, Blaauboer BJ. Evaluation of research activities and research needs to increase the impact and applicability of alternative testing strategies in risk assessment practice. Regul Toxicol Pharmacol 2011; 61:105-14. [PMID: 21782875 DOI: 10.1016/j.yrtph.2011.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 06/07/2011] [Accepted: 06/29/2011] [Indexed: 11/20/2022]
Abstract
The present paper aims at identifying strategies to increase the impact and applicability of alternative testing strategies in risk assessment. To this end, a quantitative and qualitative literature evaluation was performed on (a) current research efforts in the development of in vitro methods aiming for alternatives to animal testing, (b) the possibilities and limitations of in vitro methods for regulatory purposes and (c) the potential of physiologically-based kinetic (PBK) modeling to improve the impact and applicability of in vitro methods in risk assessment practice. Overall, the evaluation showed that the focus of state-of-the-art research activities does not seem to be optimally directed at developing in vitro alternatives for those endpoints that are most animal-demanding, such as reproductive and developmental toxicity, and carcinogenicity. A key limitation in the application of in vitro alternatives to such systemic endpoints is that in vitro methods do not provide so-called points of departure, necessary for regulators to set safe exposure limits. PBK-modeling could contribute to overcoming this limitation by providing a method that allows extrapolation of in vitro concentration-response curves to in vivo dose-response curves. However, more proofs of principle are required.
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Affiliation(s)
- Ans Punt
- Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands.
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83
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Seiler AEM, Spielmann H. The validated embryonic stem cell test to predict embryotoxicity in vitro. Nat Protoc 2011; 6:961-78. [DOI: 10.1038/nprot.2011.348] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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84
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Evaluation of 309 environmental chemicals using a mouse embryonic stem cell adherent cell differentiation and cytotoxicity assay. PLoS One 2011; 6:e18540. [PMID: 21666745 PMCID: PMC3110185 DOI: 10.1371/journal.pone.0018540] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 03/02/2011] [Indexed: 12/23/2022] Open
Abstract
The vast landscape of environmental chemicals has motivated the need for alternative methods to traditional whole-animal bioassays in toxicity testing. Embryonic stem (ES) cells provide an in vitro model of embryonic development and an alternative method for assessing developmental toxicity. Here, we evaluated 309 environmental chemicals, mostly food-use pesticides, from the ToxCast™ chemical library using a mouse ES cell platform. ES cells were cultured in the absence of pluripotency factors to promote spontaneous differentiation and in the presence of DMSO-solubilized chemicals at different concentrations to test the effects of exposure on differentiation and cytotoxicity. Cardiomyocyte differentiation (α,β myosin heavy chain; MYH6/MYH7) and cytotoxicity (DRAQ5™/Sapphire700™) were measured by In-Cell Western™ analysis. Half-maximal activity concentration (AC50) values for differentiation and cytotoxicity endpoints were determined, with 18% of the chemical library showing significant activity on either endpoint. Mining these effects against the ToxCast Phase I assays (∼500) revealed significant associations for a subset of chemicals (26) that perturbed transcription-based activities and impaired ES cell differentiation. Increased transcriptional activity of several critical developmental genes including BMPR2, PAX6 and OCT1 were strongly associated with decreased ES cell differentiation. Multiple genes involved in reactive oxygen species signaling pathways (NRF2, ABCG2, GSTA2, HIF1A) were strongly associated with decreased ES cell differentiation as well. A multivariate model built from these data revealed alterations in ABCG2 transporter was a strong predictor of impaired ES cell differentiation. Taken together, these results provide an initial characterization of metabolic and regulatory pathways by which some environmental chemicals may act to disrupt ES cell growth and differentiation.
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85
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van Dartel DAM, Piersma AH. The embryonic stem cell test combined with toxicogenomics as an alternative testing model for the assessment of developmental toxicity. Reprod Toxicol 2011; 32:235-44. [PMID: 21575713 DOI: 10.1016/j.reprotox.2011.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 04/20/2011] [Accepted: 04/29/2011] [Indexed: 01/15/2023]
Abstract
One of the most studied in vitro alternative testing methods for identification of developmental toxicity is the embryonic stem cell test (EST). Although the EST has been formally validated, the applicability domain as well as the predictability of the model needs further study to allow successful implementation of the EST as an alternative testing method in regulatory toxicity testing. Genomics technologies have already provided a proof of principle of their value in identification of toxicants such as carcinogenic compounds. Also within the EST, gene expression profiling has shown its value in the identification of developmental toxicity and in the evaluation of factors critical for risk assessment, such as dose and time responses. It is expected that the implementation of genomics into the EST will provide a more detailed end point evaluation as compared to the classical morphological scoring of differentiation cultures. Therefore, genomics may contribute to improvement of the EST, both in terms of definition of its applicability domain as well as its predictive capacity. In the present review, we present the progress that has been made with regard to the prediction of developmental toxicity using the EST combined with transcriptomics. Furthermore, we discuss the developments of additional aspects required for further optimization of the EST, including kinetics, the use of human embryonic stem cells (ESC) and computational toxicology. Finally, the current and future use of the EST model for prediction of developmental toxicity in testing strategies and in regulatory toxicity evaluations is discussed.
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Affiliation(s)
- Dorien A M van Dartel
- Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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86
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Adler S, Basketter D, Creton S, Pelkonen O, van Benthem J, Zuang V, Andersen KE, Angers-Loustau A, Aptula A, Bal-Price A, Benfenati E, Bernauer U, Bessems J, Bois FY, Boobis A, Brandon E, Bremer S, Broschard T, Casati S, Coecke S, Corvi R, Cronin M, Daston G, Dekant W, Felter S, Grignard E, Gundert-Remy U, Heinonen T, Kimber I, Kleinjans J, Komulainen H, Kreiling R, Kreysa J, Leite SB, Loizou G, Maxwell G, Mazzatorta P, Munn S, Pfuhler S, Phrakonkham P, Piersma A, Poth A, Prieto P, Repetto G, Rogiers V, Schoeters G, Schwarz M, Serafimova R, Tähti H, Testai E, van Delft J, van Loveren H, Vinken M, Worth A, Zaldivar JM. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010. Arch Toxicol 2011; 85:367-485. [PMID: 21533817 DOI: 10.1007/s00204-011-0693-2] [Citation(s) in RCA: 358] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/03/2011] [Indexed: 01/09/2023]
Abstract
The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on Consumer Safety) to identify scientific experts in five toxicological areas, i.e. toxicokinetics, repeated dose toxicity, carcinogenicity, skin sensitisation, and reproductive toxicity for which the Directive foresees that the 2013 deadline could be further extended in case alternative and validated methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between sensitisers and non-sensitisers, ahead of 2017. This would, however, not provide the complete picture of what is a safe exposure because the relative potency of a sensitiser would not be known. For toxicokinetics, the timeframe was 5-7 years to develop the models still lacking to predict lung absorption and renal/biliary excretion, and even longer to integrate the methods to fully replace the animal toxicokinetic models. For the systemic toxicological endpoints of repeated dose toxicity, carcinogenicity and reproductive toxicity, the time horizon for full replacement could not be estimated.
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Affiliation(s)
- Sarah Adler
- Centre for Documentation and Evaluation of Alternatives to Animal Experiments (ZEBET), Federal Institute for Risk Assessment (BfR), Berlin, Germany
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87
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de Jong E, Barenys M, Hermsen SAB, Verhoef A, Ossendorp BC, Bessems JGM, Piersma AH. Comparison of the mouse Embryonic Stem cell Test, the rat Whole Embryo Culture and the Zebrafish Embryotoxicity Test as alternative methods for developmental toxicity testing of six 1,2,4-triazoles. Toxicol Appl Pharmacol 2011; 253:103-11. [PMID: 21443896 DOI: 10.1016/j.taap.2011.03.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 03/15/2011] [Accepted: 03/17/2011] [Indexed: 02/01/2023]
Abstract
The relatively high experimental animal use in developmental toxicity testing has stimulated the search for alternatives that are less animal intensive. Three widely studied alternative assays are the mouse Embryonic Stem cell Test (EST), the Zebrafish Embryotoxicity Test (ZET) and the rat postimplantation Whole Embryo Culture (WEC). The goal of this study was to determine their efficacy in assessing the relative developmental toxicity of six 1,2,4-triazole compounds,(1) flusilazole, hexaconazole, cyproconazole, triadimefon, myclobutanil and triticonazole. For this purpose, we analyzed effects and relative potencies of the compounds in and among the alternative assays and compared the findings to their known in vivo developmental toxicity. Triazoles are antifungal agents used in agriculture and medicine, some of which are known to induce craniofacial and limb abnormalities in rodents. The WEC showed a general pattern of teratogenic effects, typical of exposure to triazoles, mainly consisting of reduction and fusion of the first and second branchial arches, which are in accordance with the craniofacial malformations reported after in vivo exposure. In the EST all triazole compounds inhibited cardiomyocyte differentiation concentration-dependently. Overall, the ZET gave the best correlation with the relative in vivo developmental toxicities of the tested compounds, closely followed by the EST. The relative potencies observed in the WEC showed the lowest correlation with the in vivo developmental toxicity data. These differences in the efficacy between the test systems might be due to differences in compound kinetics, in developmental stages represented and in the relative complexity of the alternative assays.
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Affiliation(s)
- Esther de Jong
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
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88
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Gene set assembly for quantitative prediction of developmental toxicity in the embryonic stem cell test. Toxicology 2011; 284:63-71. [PMID: 21473898 DOI: 10.1016/j.tox.2011.03.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 03/23/2011] [Accepted: 03/27/2011] [Indexed: 11/22/2022]
Abstract
The embryonic stem cell test (EST) is an in vitro method for predicting developmental toxicity based on compound-induced inhibition of embryonic stem cell (ESC) differentiation. We previously described how gene expression analysis in the EST can be used to describe normal ESC differentiation as well as identify compound developmental toxicity, by means of our differentiation track algorithm. In this study, we combined raw data from our three previous studies in a new integrated analysis, to identify a gene set that allows for improved prediction. By evaluating predictions of 100,000 randomly selected gene sets, we identified which genes contribute significantly to the prediction reliability. By additional cross-validation, we identified a set of 52 genes that allows for improved prediction of toxicity. The correlation between the predictions using this gene set and the magnitude of the EST endpoint was 0.85, and the gene set predicted developmental toxicity with 83% accuracy (area under the curve 89%). If compounds with ineffective data because of a too low tested concentration or too much variation between samples were excluded, even 100% accuracy could be reached based on 15 compounds. This novel gene set consists mainly of genes involved in the stem cell differentiation or other developmental processes. We expect that this set can be of use in future studies aimed at improving the EST for risk assessment, thus making a next step towards regulatory implementation of this method.
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89
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Riebeling C, Pirow R, Becker K, Buesen R, Eikel D, Kaltenhäuser J, Meyer F, Nau H, Slawik B, Visan A, Volland J, Spielmann H, Luch A, Seiler A. The embryonic stem cell test as tool to assess structure-dependent teratogenicity: the case of valproic acid. Toxicol Sci 2011; 120:360-70. [PMID: 21227905 PMCID: PMC3061479 DOI: 10.1093/toxsci/kfr001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 01/03/2011] [Indexed: 01/21/2023] Open
Abstract
Teratogenicity can be predicted in vitro using the embryonic stem cell test (EST). The EST, which is based on the morphometric measurement of cardiomyocyte differentiation and cytotoxicity parameters, represents a scientifically validated method for the detection and classification of chemicals according to their teratogenic potency. Furthermore, an abbreviated protocol applying flow cytometry of intracellular marker proteins to determine differentiation into the cardiomyocyte lineage is available. Although valproic acid (VPA) is in worldwide clinical use as antiepileptic drug, it exhibits two severe side effects, i.e., teratogenicity and hepatotoxicity. These limitations have led to extensive research into derivatives of VPA. Here we chose VPA as model compound to test the applicability domain and to further evaluate the reliability of the EST. To this end, we study six closely related congeners of VPA and demonstrate that both the standard and the molecular flow cytometry-based EST are well suited to indicate differences in the teratogenic potency among VPA analogs that differ only in chirality or side chain length. Our data show that identical results can be obtained by using the standard EST or a shortened protocol based on flow cytometry of intracellular marker proteins. Both in vitro protocols enable to reliably determine differentiation of murine stem cells toward the cardiomyocyte lineage and to assess its chemical-mediated inhibition.
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Affiliation(s)
- Christian Riebeling
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Ralph Pirow
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Klaus Becker
- Bayer Schering Pharma AG, Nonclinical Drug Safety, Genetic Toxicology, 13342 Berlin, Germany
| | - Roland Buesen
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Daniel Eikel
- Institute of Food Toxicology and Chemical Analysis, University of Veterinary Medicine Hanover, 30173 Hanover, Germany
| | - Johanna Kaltenhäuser
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
- Bayer Schering Pharma AG, Nonclinical Drug Safety, Genetic Toxicology, 13342 Berlin, Germany
| | - Frauke Meyer
- Nycomed GmbH, Institute for Pharmacology and Preclinical Drug Safety (IPAS), Hamburg, 22885 Barsbüttel, Germany
| | - Heinz Nau
- Institute of Food Toxicology and Chemical Analysis, University of Veterinary Medicine Hanover, 30173 Hanover, Germany
| | - Birgitta Slawik
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Anke Visan
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Jutta Volland
- Nycomed GmbH, Institute for Pharmacology and Preclinical Drug Safety (IPAS), Hamburg, 22885 Barsbüttel, Germany
| | - Horst Spielmann
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Andreas Luch
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
| | - Andrea Seiler
- German Federal Institute for Risk Assessment (BfR), Center for Alternative Methods to Animal Experiments—ZEBET, 12277 Berlin, Germany
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90
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Defined culture medium for stem cell differentiation: applicability of serum-free conditions in the mouse embryonic stem cell test. Toxicol In Vitro 2011; 25:914-21. [PMID: 21376803 DOI: 10.1016/j.tiv.2011.02.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 02/23/2011] [Accepted: 02/25/2011] [Indexed: 11/22/2022]
Abstract
The embryonic stem cell test (EST) is a validated method to assess the developmental toxicity potency of chemicals. It was developed to reduce animal use and allow faster testing for hazard assessment. The cells used in this method are maintained and differentiated in media containing foetal calf serum. This animal product is of considerable variation in quality, and individual batches require extensive testing for their applicability in the EST. Moreover, its production involves a large number of foetuses and possible animal suffering. We demonstrate the serum-free medium and feeder cell-free maintenance of the mouse embryonic stem cell line D3 and investigate the use of specific growth factors for induction of cardiac differentiation. Using a combination of bone morphogenetic protein-2, bone morphogenetic protein-4, activin A and ascorbic acid, embryoid bodies efficiently differentiated into contracting myocardium. Additionally, examining levels of intracellular marker proteins by flow cytometry not only confirmed differentiation into cardiomyocytes, but demonstrated significant differentiation into neuronal cells in the same time frame. Thus, this approach might allow for simultaneous detection of developmental effects on both early mesodermal and neuroectodermal differentiation. The serum-free conditions for maintenance and differentiation of D3 cells described here enhance the transferability and standardisation and hence the performance of the EST.
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91
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Thomson J, Johnson K, Chapin R, Stedman D, Kumpf S, Ozolinš TR. Not a walk in the park: the ECVAM whole embryo culture model challenged with pharmaceuticals and attempted improvements with random forest design. ACTA ACUST UNITED AC 2011; 92:111-21. [DOI: 10.1002/bdrb.20289] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 02/02/2011] [Indexed: 11/08/2022]
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92
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Louisse J, Gönen S, Rietjens IMCM, Verwei M. Relative developmental toxicity potencies of retinoids in the embryonic stem cell test compared with their relative potencies in in vivo and two other in vitro assays for developmental toxicity. Toxicol Lett 2011; 203:1-8. [PMID: 21362465 DOI: 10.1016/j.toxlet.2011.02.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 02/10/2011] [Accepted: 02/14/2011] [Indexed: 10/18/2022]
Abstract
The present study determines the relative developmental toxicity potencies of retinoids in the embryonic stem (ES)-D3 cell differentiation assay of the embryonic stem cell test, and compares the outcomes with their relative potencies in in vivo and two other in vitro assays for developmental toxicity. The results reveal that the potency ranking obtained in the ES-D3 cell differentiation assay is similar to the reported potency rankings in the two other in vitro assays for developmental toxicity. TTNPB ((E)-4[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid) was the most potent retinoid, whereas etretinate and retinol had the lowest potency. All-trans-retinoic acid, 13-cis-retinoic acid, 9-cis-retinoic acid and acitretin showed an intermediate potency. In vivo potency rankings of the developmental toxicity of retinoids appear to be dependent on the species and/or exposure regimens used. The obtained in vitro potency ranking does not completely correspond with the in vivo potency rankings, although TTNPB is correctly predicted to be the most potent and retinol the least potent congener. The lack of in vivo kinetic processes in the ES-D3 cell differentiation assay might explain the deviating potency predictions of some retinoids. Therefore, knowledge on the species-dependent in vivo kinetics is essential when using in vitro toxicity data for the estimation of in vivo developmental toxicity potencies within series of related compounds.
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Affiliation(s)
- Jochem Louisse
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703 HE Wageningen, The Netherlands.
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93
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Wobus AM, Löser P. Present state and future perspectives of using pluripotent stem cells in toxicology research. Arch Toxicol 2011; 85:79-117. [PMID: 21225242 PMCID: PMC3026927 DOI: 10.1007/s00204-010-0641-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 12/21/2010] [Indexed: 02/08/2023]
Abstract
The use of novel drugs and chemicals requires reliable data on their potential toxic effects on humans. Current test systems are mainly based on animals or in vitro–cultured animal-derived cells and do not or not sufficiently mirror the situation in humans. Therefore, in vitro models based on human pluripotent stem cells (hPSCs) have become an attractive alternative. The article summarizes the characteristics of pluripotent stem cells, including embryonic carcinoma and embryonic germ cells, and discusses the potential of pluripotent stem cells for safety pharmacology and toxicology. Special attention is directed to the potential application of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) for the assessment of developmental toxicology as well as cardio- and hepatotoxicology. With respect to embryotoxicology, recent achievements of the embryonic stem cell test (EST) are described and current limitations as well as prospects of embryotoxicity studies using pluripotent stem cells are discussed. Furthermore, recent efforts to establish hPSC-based cell models for testing cardio- and hepatotoxicity are presented. In this context, methods for differentiation and selection of cardiac and hepatic cells from hPSCs are summarized, requirements and implications with respect to the use of these cells in safety pharmacology and toxicology are presented, and future challenges and perspectives of using hPSCs are discussed.
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Affiliation(s)
- Anna M Wobus
- In Vitro Differentiation Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, 06466 Gatersleben, Germany.
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94
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van Dartel DAM, Pennings JLA, de la Fonteyne LJJ, Brauers KJJ, Claessen S, van Delft JH, Kleinjans JCS, Piersma AH. Concentration-dependent gene expression responses to flusilazole in embryonic stem cell differentiation cultures. Toxicol Appl Pharmacol 2010; 251:110-8. [PMID: 21192963 DOI: 10.1016/j.taap.2010.12.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 12/15/2010] [Accepted: 12/17/2010] [Indexed: 01/09/2023]
Abstract
The murine embryonic stem cell test (EST) is designed to evaluate developmental toxicity based on compound-induced inhibition of embryonic stem cell (ESC) differentiation into cardiomyocytes. The addition of transcriptomic evaluation within the EST may result in enhanced predictability and improved characterization of the applicability domain, therefore improving usage of the EST for regulatory testing strategies. Transcriptomic analyses assessing factors critical for risk assessment (i.e. dose) are needed to determine the value of transcriptomic evaluation in the EST. Here, using the developmentally toxic compound, flusilazole, we investigated the effect of compound concentration on gene expression regulation and toxicity prediction in ESC differentiation cultures. Cultures were exposed for 24 h to multiple concentrations of flusilazole (0.54-54 μM) and RNA was isolated. In addition, we sampled control cultures 0, 24, and 48 h to evaluate the transcriptomic status of the cultures across differentiation. Transcriptomic profiling identified a higher sensitivity of development-related processes as compared to cell division-related processes in flusilazole-exposed differentiation cultures. Furthermore, the sterol synthesis-related mode of action of flusilazole toxicity was detected. Principal component analysis using gene sets related to normal ESC differentiation was used to describe the dynamics of ESC differentiation, defined as the 'differentiation track'. The concentration-dependent effects on development were reflected in the significance of deviation of flusilazole-exposed cultures from this transcriptomic-based differentiation track. Thus, the detection of developmental toxicity in EST using transcriptomics was shown to be compound concentration-dependent. This study provides further insight into the possible application of transcriptomics in the EST as an improved alternative model system for developmental toxicity testing.
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Affiliation(s)
- Dorien A M van Dartel
- Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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95
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Daston GP, Chapin RE, Scialli AR, Piersma AH, Carney EW, Rogers JM, Friedman JM. A different approach to validating screening assays for developmental toxicity. ACTA ACUST UNITED AC 2010; 89:526-30. [DOI: 10.1002/bdrb.20276] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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96
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Coordinated waves of gene expression during neuronal differentiation of embryonic stem cells as basis for novel approaches to developmental neurotoxicity testing. Cell Death Differ 2010; 18:383-95. [PMID: 20865013 DOI: 10.1038/cdd.2010.109] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
As neuronal differentiation of embryonic stem cells (ESCs) recapitulates embryonic neurogenesis, disturbances of this process may model developmental neurotoxicity (DNT). To identify the relevant steps of in vitro neurodevelopment, we implemented a differentiation protocol yielding neurons with desired electrophysiological properties. Results from focussed transcriptional profiling suggested that detection of non-cytotoxic developmental disturbances triggered by toxicants such as retinoic acid (RA) or cyclopamine was possible. Therefore, a broad transcriptional profile of the 20-day differentiation process was obtained. Cluster analysis of expression kinetics, and bioinformatic identification of overrepresented gene ontologies revealed waves of regulation relevant for DNT testing. We further explored the concept of superimposed waves as descriptor of ordered, but overlapping biological processes. The initial wave of transcripts indicated reorganization of chromatin and epigenetic changes. Then, a transient upregulation of genes involved in the formation and patterning of neuronal precursors followed. Simultaneously, a long wave of ongoing neuronal differentiation started. This was again superseded towards the end of the process by shorter waves of neuronal maturation that yielded information on specification, extracellular matrix formation, disease-associated genes and the generation of glia. Short exposure to lead during the final differentiation phase, disturbed neuronal maturation. Thus, the wave kinetics and the patterns of neuronal specification define the time windows and end points for examination of DNT.
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97
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West PR, Weir AM, Smith AM, Donley EL, Cezar GG. Predicting human developmental toxicity of pharmaceuticals using human embryonic stem cells and metabolomics. Toxicol Appl Pharmacol 2010; 247:18-27. [DOI: 10.1016/j.taap.2010.05.007] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 05/11/2010] [Accepted: 05/13/2010] [Indexed: 10/19/2022]
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98
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van Dartel DAM, Pennings JLA, de la Fonteyne LJJ, van Herwijnen MH, van Delft JH, van Schooten FJ, Piersma AH. Monitoring developmental toxicity in the embryonic stem cell test using differential gene expression of differentiation-related genes. Toxicol Sci 2010; 116:130-9. [PMID: 20421339 DOI: 10.1093/toxsci/kfq127] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The embryonic stem cell test (EST) has been designed to predict developmental toxicity based upon compound-induced inhibition of embryonic stem cell (ESC) differentiation. The end point scoring, the test duration, and the definition of the predictivity and the applicability domain require improvements to facilitate implementation of the EST into regulatory testing strategies. The use of transcriptomics to study compound-induced differentiation modulation may improve the EST in each of these aspects. ESC differentiation was induced, and cell samples were collected after 0, 24, and 48 h of differentiation. Additionally, samples were collected that were 24 h exposed to one of five developmentally toxic compounds or a nondevelopmentally toxic compound. All samples were hybridized to Affymetrix GeneChips, and analyses revealed that 26 genes were significantly regulated both during ESC differentiation and by exposure to each of the developmentally toxic compounds tested. Using principal component analysis, we defined a "differentiation track" on the basis of this gene list, which represents ESC differentiation. We showed that significant deviation from the differentiation track was in line with the developmental toxic properties of the compounds. The significance of deviation was analyzed using the leave-one-out cross-validation, which showed a favorable prediction of toxicity in the system. Our findings show that gene expression signatures can be used to identify developmental toxicant-induced differentiation modulation. In addition, studying compound-induced effects at an early stage of differentiation combined with transcriptomics leads to increased objectivity in determining differentiation inhibition and to a reduction of the test duration. Furthermore, this approach may improve the predictivity and applicability domain of the EST.
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Affiliation(s)
- Dorien A M van Dartel
- Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands.
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