Application of Microelectrode Array Approaches to Neurotoxicity Testing and Screening

Shafer, Timothy J.

doi:10.1007/978-3-030-11135-9_12

Cited by 31 publications

(27 citation statements)

References 83 publications

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“…For the human DNT in vitro testing battery there are comparative rodent models available for most of the human assays. Human NPC1-5 is copied by rat or mouse NPC1-5 (Gassmann et al, 2010(Gassmann et al, , 2012Baumann et al, 2015, rat cortical synaptogenesis (Harrill et al, 2018) and rat NNF (Shafer, 2019;Frank et al, 2018) can be accompanied by a human synaptogenesis assay (Pistollato et al, 2014) and a human NNF assay (Bartmann, Masjosthusmann, Fritsche, unpublished). As an example, responses of the endpoint-specific control, the PKC inhibitor Bis-I can be compared between the rat and human NNF assay (Figure 62).…”

Section: How Can Be Dealt With Species-specific Effects?mentioning

confidence: 99%

Establishment of an a priori protocol for the implementation and interpretation of an in‐vitro testing battery for the assessment of developmental neurotoxicity

Masjosthusmann

Blum

Bartmann

et al. 2020

EFS3

156

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In this project we set up a human cell-based DNT in vitro testing strategy that is based on test methods with high readiness and data generated therefrom. The methods underwent a fit-for-purpose evaluation that considered four key elements: 1. The test system, 2. the exposure scheme, 3. the assay and analytical endpoint(s) and 4. the classification model. This testing battery was challenged with 119 chemicals for which rich toxicological information was available (for some of them also on their DNT hazard). Testing was performed in 5 test systems measuring 10 DNT-specific endpoints and additional 9 viability/ cytotoxicity-related parameters. For approximately half of the compounds, additional and complementary data from DNT in vitro tests was added by the US-EPA. This extended battery was also evaluated. Testing results revealed that the test methods of this current DNT in vitro battery are reliable and reproducible. The endpoints had to a large extent low redundancy. Battery performance, as assessed with compounds well-characterized for DNT hazard had a sensitivity of 82.7 % and a specificity of 88.2 %. Gap analyses suggested that radial, astro-and microglia as well as myelination endpoints may be added to the battery. Two case studies, one for screening and prioritization of 14 flame retardants, and one on hazard characterization of 2 pesticides, were presented. Hypothetical AOPs were developed based on the latter case study. In conclusion, the DNT testing strategy explored here is a very promising first approach for DNT hazard identification and characterization. The performance is encouraging and may be improved by inclusion of further tests. Some uncertainties in DNT in vitro battery testing outcomes could be reduced by incorporating test data and modelling approaches related to in vitro and in vivo toxicokinetics of test compounds.

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Section: How Can Be Dealt With Species-specific Effects?mentioning

confidence: 99%

Establishment of an a priori protocol for the implementation and interpretation of an in‐vitro testing battery for the assessment of developmental neurotoxicity

Masjosthusmann

Blum

Bartmann

et al. 2020

EFS3

156

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“…Another method is to culture cells on microelectrode arrays (MEA). These arrays record the extracellular field potential of cultured neurons and thereby give a comprehensive overview of the electric activity of cultured neuronal networks (Hofrichter et al 2017 ; Hogberg et al 2011 ; Nimtz et al 2020 ; Shafer 2019 ; Strickland et al 2018 ; Vassallo et al 2017 ).…”

Section: Introductionmentioning

confidence: 99%

A human stem cell-derived test system for agents modifying neuronal N-methyl-d-aspartate-type glutamate receptor Ca2+-signalling

et al. 2021

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Methods to assess neuronal receptor functions are needed in toxicology and for drug development. Human-based test systems that allow studies on glutamate signalling are still scarce. To address this issue, we developed and characterized pluripotent stem cell (PSC)-based neural cultures capable of forming a functional network. Starting from a stably proliferating neuroepithelial stem cell (NESC) population, we generate “mixed cortical cultures” (MCC) within 24 days. Characterization by immunocytochemistry, gene expression profiling and functional tests (multi-electrode arrays) showed that MCC contain various functional neurotransmitter receptors, and in particular, the N-methyl-d-aspartate subtype of ionotropic glutamate receptors (NMDA-R). As this important receptor is found neither on conventional neural cell lines nor on most stem cell-derived neurons, we focused here on the characterization of rapid glutamate-triggered Ca2+ signalling. Changes of the intracellular free calcium ion concentration ([Ca2+]i) were measured by fluorescent imaging as the main endpoint, and a method to evaluate and quantify signals in hundreds of cells at the same time was developed. We observed responses to glutamate in the low µM range. MCC responded to kainate and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and a subpopulation of 50% had functional NMDA-R. The receptor was modulated by Mg2+, Zn2+ and Pb2+ in the expected ways, and various toxicologically relevant agonists (quinolinic acid, ibotenic acid, domoic acid) triggered [Ca2+]i responses in MCC. Antagonists, such as phencyclidine, ketamine and dextromethorphan, were also readily identified. Thus, the MCC developed here may fill an important gap in the panel of test systems available to characterize the effects of chemicals on neurotransmitter receptors.

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“…Advances in MEA technology [8,19] have led to adoption of MEAs for neurotoxicological screening [20] Given the potential of NAS to consolidate many functional MEA parameters, we sought to determine its applicability to neurotoxicity screening.…”

Section: Resultsmentioning

confidence: 99%

“…Advances in MEA technology, including multi-well MEA plates, incubated recording setups, and constantly improving software, allow for higher throughput than previously possible [18,19], though analysis has traditionally been limited to simple parameters, primarily mean firing rate. Only recently have researchers begun incorporating advanced metrics of network activity in these screening approaches [20–22]. These advanced metrics have provided researchers with tools to record from entire neuronal populations and analyze complex neuronal network dynamics.…”

Section: Discussionmentioning

confidence: 99%

Development of an objective index, neural activity score (NAS), reveals neural network ontogeny and treatment effects on microelectrode arrays

Passaro

Aydin

Saif

et al. 2020

Preprint

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Microelectrode arrays (MEAs) are valuable tools for electrophysiological analysis at a cellular population level, providing assessment of neural network health and development. Analysis can be complex, however, requiring intensive processing of large high-dimensional data sets consisting of many activity parameters. As a result, valuable information is lost, as studies subjectively report relatively few metrics in the interest of simplicity and clarity.From a screening perspective, many groups report simple overall activity; we are more interested in culture health and changes in network connectivity that may not be evident from basic activity parameters. For example, general changes in overall firing rate – the most commonly reported parameter – provide no information on network development or burst character, which could change independently. Our goal was to develop a fast objective process to capture most, if not all, the valuable information gained when using MEAs in neural development and toxicity studies.We implemented principal component analysis (PCA) to reduce the high dimensionality of MEA data. Upon analysis, we found that the first principal component was strongly correlated to time, representing neural culture development; therefore, factor loadings were used to create a single index score – named neural activity score (NAS) – reflective of neural maturation. To validate this score, we applied it to studies analyzing various treatments. In all cases, NAS accurately recapitulated expected results, suggesting this method is viable. This approach may be improved with larger training data sets and can be shared with other researchers using MEAs to analyze complicated treatment effects and multicellular interactions.Author SummaryAnalyzing neural activity has important applications such as basic neuroscience research, understanding neurological diseases, drug development, and toxicity screening. Technology for recording neural activity continues to develop, producing large data sets that provide complex information about neuronal function. One specific technology, microelectrode arrays (MEAs), has recently given researchers the ability to record developing neural networks with potential to provide valuable insight into developmental processes and pathological conditions. However, the complex data generated by these systems can be challenging to analyze objectively and quantitatively, hindering the potential of MEAs, especially for high-throughput approaches, such as drug development and toxicity screening, which require quick, simple, and accurate quantification. Therefore, we have developed an index for simple quantification and evaluation of neural network maturation and the effects of perturbation. We present validation of our approach using several treatments and culture conditions, as well as a meta-analysis of toxicological screening data to compare our approach to current methods. In addition to providing a simple quantification method for neural network activity in various conditions, our method provides potential for improved results interpretation in toxicity screening and drug development.

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Application of Microelectrode Array Approaches to Neurotoxicity Testing and Screening

Cited by 31 publications

References 83 publications

Establishment of an a priori protocol for the implementation and interpretation of an in‐vitro testing battery for the assessment of developmental neurotoxicity

Establishment of an a priori protocol for the implementation and interpretation of an in‐vitro testing battery for the assessment of developmental neurotoxicity

A human stem cell-derived test system for agents modifying neuronal N-methyl-d-aspartate-type glutamate receptor Ca2+-signalling

Development of an objective index, neural activity score (NAS), reveals neural network ontogeny and treatment effects on microelectrode arrays

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