1
|
Martin MM, Carpenter AF, Shafer TJ, Paul Friedman K, Carstens KE. Chemical effects on neural network activity: Comparison of acute versus network formation exposure in microelectrode array assays. Toxicology 2024; 505:153842. [PMID: 38788893 DOI: 10.1016/j.tox.2024.153842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/08/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
New approach methodologies (NAMs) can address information gaps on potential neurotoxicity or developmental neurotoxicity hazard for data-poor chemicals. Two assays have been previously developed using microelectrode arrays (MEA), a technology which measures neural activity. The MEA acute network function assay (AcN) uses dissociated rat cortical cells cultured at postnatal day 0 and evaluates network activity during a 40-minute chemical exposure on day in vitro (DIV)13 or 15. In contrast, the MEA network formation assay (NFA) uses a developmental exposure paradigm spanning DIV0 through DIV12. Measures of network activity over time at DIV5, 7, 9, and 12 in the NFA are reduced to an estimated area under the curve to facilitate concentration-response evaluation. Here, we evaluated the hypothesis that chemicals with effects in the AcN also perturb the NFA by examining quantitative and qualitative concordance between assays. Out of 243 chemicals screened in both assays, we observed 70.3% concordance between the AcN and NFA after eliminating activity inferred to be cytotoxic (selective activity), with the majority of discordance explained by chemicals that altered selective activity in the AcN but not NFA. The NFA detected more active chemicals when evaluating activity associated with cytotoxicity. Median potency values were lower in the NFA compared to the AcN, but within-chemical potency values were not uniformly lower in the NFA than the AcN. Lastly, the AcN and NFA captured unique bioactivity fingerprints; the AcN was more informative for identifying chemicals with a shared mode of action, while the NFA provided information relevant to developmental exposure. Taken together, this analysis provides a rationale for using both approaches for chemical evaluation with consideration of the context of use, such as screening/ prioritization, hazard identification, or to address questions regarding biological mechanism or function.
Collapse
Affiliation(s)
- Melissa M Martin
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Amy F Carpenter
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA; Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Timothy J Shafer
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Katie Paul Friedman
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Kelly E Carstens
- Computational Toxicology & Bioinformatics Branch, Biomolecular and Computational Toxicology Division, CCTE/ORD, US. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| |
Collapse
|
2
|
Silva MH. Investigating open access new approach methods (NAM) to assess biological points of departure: A case study with 4 neurotoxic pesticides. Curr Res Toxicol 2024; 6:100156. [PMID: 38404712 PMCID: PMC10891343 DOI: 10.1016/j.crtox.2024.100156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/28/2023] [Accepted: 02/09/2024] [Indexed: 02/27/2024] Open
Abstract
Open access new approach methods (NAM) in the US EPA ToxCast program and NTP Integrated Chemical Environment (ICE) were used to investigate activities of four neurotoxic pesticides: endosulfan, fipronil, propyzamide and carbaryl. Concordance of in vivo regulatory points of departure (POD) adjusted for interspecies extrapolation (AdjPOD) to modelled human Administered Equivalent Dose (AEDHuman) was assessed using 3-compartment or Adult/Fetal PBTK in vitro to in vivo extrapolation. Model inputs were from Tier 1 (High throughput transcriptomics: HTTr, high throughput phenotypic profiling: HTPP) and Tier 2 (single target: ToxCast) assays. HTTr identified gene expression signatures associated with potential neurotoxicity for endosulfan, propyzamide and carbaryl in non-neuronal MCF-7 and HepaRG cells. The HTPP assay in U-2 OS cells detected potent effects on DNA endpoints for endosulfan and carbaryl, and mitochondria with fipronil (propyzamide was inactive). The most potent ToxCast assays were concordant with specific components of each chemical mode of action (MOA). Predictive adult IVIVE models produced fold differences (FD) < 10 between the AEDHuman and the measured in vivo AdjPOD. The 3-compartment model was concordant (i.e., smallest FD) for endosulfan, fipronil and carbaryl, and PBTK was concordant for propyzamide. The most potent AEDHuman predictions for each chemical showed HTTr, HTPP and ToxCast were mainly concordant with in vivo AdjPODs but assays were less concordant with MOAs. This was likely due to the cell types used for testing and/or lack of metabolic capabilities and pathways available in vivo. The Fetal PBTK model had larger FDs than adult models and was less predictive overall.
Collapse
|
3
|
Gerber LS, van Kleef RGDM, Fokkens P, Cassee FR, Westerink RH. In vitro neurotoxicity screening of engine oil- and hydraulic fluid-derived aircraft cabin bleed-air contamination. Neurotoxicology 2023; 96:184-196. [PMID: 37120036 DOI: 10.1016/j.neuro.2023.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/01/2023]
Abstract
In most airplanes, cabin air is extracted from the turbine compressors, so-called bleed air. Bleed air can become contaminated by leakage of engine oil or hydraulic fluid and possible neurotoxic constituents, like triphenyl phosphate (TPhP) and tributyl phosphate (TBP). The aim of this study was to characterize the neurotoxic hazard of TBP and TPhP, and to compare this with the possible hazard of fumes originating from engine oils and hydraulic fluids in vitro. Effects on spontaneous neuronal activity were recorded in rat primary cortical cultures grown on microelectrode arrays following exposure for 0.5h (acute), and 24h and 48h (prolonged) to TBP and TPhP (0.01 - 100µM) or fume extracts (1 - 100µg/mL) prepared from four selected engine oils and two hydraulic fluids by a laboratory bleed air simulator. TPhP and TBP concentration-dependently reduced neuronal activity with equal potency, particularly during acute exposure (TPhP IC50: 10 - 12µM; TBP IC50: 15 - 18µM). Engine oil-derived fume extracts persistently reduced neuronal activity. Hydraulic fluid-derived fume extracts showed a stronger inhibition during 0.5h exposure, but the degree of inhibition attenuates during 48h. Overall, fume extracts from hydraulic fluids were more potent than those from engine oils, in particular during 0.5h exposure, although the higher toxicity is unlikely to be due only to higher levels of TBP and TPhP in hydraulic fluids. Our combined data show that bleed air contaminants originating from selected engine oils or hydraulic fluids exhibit neurotoxic hazard in vitro, with fumes derived from the selected hydraulic fluids being most potent.
Collapse
Affiliation(s)
- Lora-Sophie Gerber
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Regina G D M van Kleef
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Paul Fokkens
- National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Flemming R Cassee
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Remco Hs Westerink
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
| |
Collapse
|
4
|
Keil-Stietz K, Lein PJ. Gene×environment interactions in autism spectrum disorders. Curr Top Dev Biol 2022; 152:221-284. [PMID: 36707213 PMCID: PMC10496028 DOI: 10.1016/bs.ctdb.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
There is credible evidence that environmental factors influence individual risk and/or severity of autism spectrum disorders (hereafter referred to as autism). While it is likely that environmental chemicals contribute to the etiology of autism via multiple mechanisms, identifying specific environmental factors that confer risk for autism and understanding how they contribute to the etiology of autism has been challenging, in part because the influence of environmental chemicals likely varies depending on the genetic substrate of the exposed individual. Current research efforts are focused on elucidating the mechanisms by which environmental chemicals interact with autism genetic susceptibilities to adversely impact neurodevelopment. The goal is to not only generate insights regarding the pathophysiology of autism, but also inform the development of screening platforms to identify specific environmental factors and gene×environment (G×E) interactions that modify autism risk. Data from such studies are needed to support development of intervention strategies for mitigating the burden of this neurodevelopmental condition on individuals, their families and society. In this review, we discuss environmental chemicals identified as putative autism risk factors and proposed mechanisms by which G×E interactions influence autism risk and/or severity using polychlorinated biphenyls (PCBs) as an example.
Collapse
Affiliation(s)
- Kimberly Keil-Stietz
- Department of Comparative Biosciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, United States
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, United States.
| |
Collapse
|
5
|
Wlodkowic D, Jansen M. High-throughput screening paradigms in ecotoxicity testing: Emerging prospects and ongoing challenges. CHEMOSPHERE 2022; 307:135929. [PMID: 35944679 DOI: 10.1016/j.chemosphere.2022.135929] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/09/2022] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
The rapidly increasing number of new production chemicals coupled with stringent implementation of global chemical management programs necessities a paradigm shift towards boarder uses of low-cost and high-throughput ecotoxicity testing strategies as well as deeper understanding of cellular and sub-cellular mechanisms of ecotoxicity that can be used in effective risk assessment. The latter will require automated acquisition of biological data, new capabilities for big data analysis as well as computational simulations capable of translating new data into in vivo relevance. However, very few efforts have been so far devoted into the development of automated bioanalytical systems in ecotoxicology. This is in stark contrast to standardized and high-throughput chemical screening and prioritization routines found in modern drug discovery pipelines. As a result, the high-throughput and high-content data acquisition in ecotoxicology is still in its infancy with limited examples focused on cell-free and cell-based assays. In this work we outline recent developments and emerging prospects of high-throughput bioanalytical approaches in ecotoxicology that reach beyond in vitro biotests. We discuss future importance of automated quantitative data acquisition for cell-free, cell-based as well as developments in phytotoxicity and in vivo biotests utilizing small aquatic model organisms. We also discuss recent innovations such as organs-on-a-chip technologies and existing challenges for emerging high-throughput ecotoxicity testing strategies. Lastly, we provide seminal examples of the small number of successful high-throughput implementations that have been employed in prioritization of chemicals and accelerated environmental risk assessment.
Collapse
Affiliation(s)
- Donald Wlodkowic
- The Neurotox Lab, School of Science, RMIT University, Melbourne, VIC, 3083, Australia.
| | - Marcus Jansen
- LemnaTec GmbH, Nerscheider Weg 170, 52076, Aachen, Germany
| |
Collapse
|
6
|
Crofton KM, Bassan A, Behl M, Chushak YG, Fritsche E, Gearhart JM, Marty MS, Mumtaz M, Pavan M, Ruiz P, Sachana M, Selvam R, Shafer TJ, Stavitskaya L, Szabo DT, Szabo ST, Tice RR, Wilson D, Woolley D, Myatt GJ. Current status and future directions for a neurotoxicity hazard assessment framework that integrates in silico approaches. COMPUTATIONAL TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2022; 22:100223. [PMID: 35844258 PMCID: PMC9281386 DOI: 10.1016/j.comtox.2022.100223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Neurotoxicology is the study of adverse effects on the structure or function of the developing or mature adult nervous system following exposure to chemical, biological, or physical agents. The development of more informative alternative methods to assess developmental (DNT) and adult (NT) neurotoxicity induced by xenobiotics is critically needed. The use of such alternative methods including in silico approaches that predict DNT or NT from chemical structure (e.g., statistical-based and expert rule-based systems) is ideally based on a comprehensive understanding of the relevant biological mechanisms. This paper discusses known mechanisms alongside the current state of the art in DNT/NT testing. In silico approaches available today that support the assessment of neurotoxicity based on knowledge of chemical structure are reviewed, and a conceptual framework for the integration of in silico methods with experimental information is presented. Establishing this framework is essential for the development of protocols, namely standardized approaches, to ensure that assessments of NT and DNT based on chemical structures are generated in a transparent, consistent, and defendable manner.
Collapse
Affiliation(s)
| | - Arianna Bassan
- Innovatune srl, Via Giulio Zanon 130/D, 35129 Padova,
Italy
| | - Mamta Behl
- Division of the National Toxicology Program, National
Institutes of Environmental Health Sciences, Durham, NC 27709, USA
| | - Yaroslav G. Chushak
- Henry M Jackson Foundation for the Advancement of Military
Medicine, Wright-Patterson AFB, OH 45433, USA
| | - Ellen Fritsche
- IUF – Leibniz Research Institute for Environmental
Medicine & Medical Faculty Heinrich-Heine-University, Düsseldorf,
Germany
| | - Jeffery M. Gearhart
- Henry M Jackson Foundation for the Advancement of Military
Medicine, Wright-Patterson AFB, OH 45433, USA
| | | | - Moiz Mumtaz
- Agency for Toxic Substances and Disease Registry, US
Department of Health and Human Services, Atlanta, GA, USA
| | - Manuela Pavan
- Innovatune srl, Via Giulio Zanon 130/D, 35129 Padova,
Italy
| | - Patricia Ruiz
- Agency for Toxic Substances and Disease Registry, US
Department of Health and Human Services, Atlanta, GA, USA
| | - Magdalini Sachana
- Environment Health and Safety Division, Environment
Directorate, Organisation for Economic Co-Operation and Development (OECD), 75775
Paris Cedex 16, France
| | - Rajamani Selvam
- Office of Clinical Pharmacology, Office of Translational
Sciences, Center for Drug Evaluation and Research (CDER), U.S. Food and Drug
Administration (FDA), Silver Spring, MD 20993, USA
| | - Timothy J. Shafer
- Biomolecular and Computational Toxicology Division, Center
for Computational Toxicology and Exposure, US EPA, Research Triangle Park, NC,
USA
| | - Lidiya Stavitskaya
- Office of Clinical Pharmacology, Office of Translational
Sciences, Center for Drug Evaluation and Research (CDER), U.S. Food and Drug
Administration (FDA), Silver Spring, MD 20993, USA
| | | | | | | | - Dan Wilson
- The Dow Chemical Company, Midland, MI 48667, USA
| | | | - Glenn J. Myatt
- Instem, Columbus, OH 43215, USA
- Corresponding author.
(G.J. Myatt)
| |
Collapse
|
7
|
Tomasello DL, Wlodkowic D. Noninvasive Electrophysiology: Emerging Prospects in Aquatic Neurotoxicity Testing. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4788-4794. [PMID: 35196004 DOI: 10.1021/acs.est.1c08471] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The significance of neurotoxicological risks associated with anthropogenic pollution is gaining increasing recognition worldwide. In this regard, perturbations in behavioral traits upon exposure to environmentally relevant concentrations of neurotoxic and neuro-modulating contaminants have been linked to diminished ecological fitness of many aquatic species. Despite an increasing interest in behavioral testing in aquatic ecotoxicology there is, however, a notable gap in understanding of the neurophysiological foundations responsible for the altered behavioral phenotypes. One of the canonical approaches to explain the mechanisms of neuro-behavioral changes is functional analysis of neuronal transmission. In aquatic animals it requires, however, invasive, complex, and time-consuming electrophysiology techniques. In this perspective, we highlight emerging prospects of noninvasive, in situ electrophysiology based on multielectrode arrays (MEAs). This technology has only recently been pioneered for the detection and analysis of transient electrical signals in the central nervous system of small model organisms such as zebrafish. The analysis resembles electroencephalography (EEG) applications and provides an appealing strategy for mechanistic explorative studies as well as routine neurotoxicity risk assessment. We outline the prospective future applications and existing challenges of this emerging analytical strategy that is poised to bring new vistas for aquatic ecotoxicology such as greater mechanistic understanding of eco-neurotoxicity and thus more robust risk assessment protocols.
Collapse
Affiliation(s)
- Danielle L Tomasello
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, United States
| | - Donald Wlodkowic
- The Neurotox Lab, School of Science, RMIT University, Melbourne, Victoria 3083, Australia
| |
Collapse
|
8
|
Dobreniecki S, Mendez E, Lowit A, Freudenrich TM, Wallace K, Carpenter A, Wetmore BA, Kreutz A, Korol-Bexell E, Friedman KP, Shafer TJ. Integration of toxicodynamic and toxicokinetic new approach methods into a weight-of-evidence analysis for pesticide developmental neurotoxicity assessment: A case-study with DL- and L-glufosinate. Regul Toxicol Pharmacol 2022; 131:105167. [PMID: 35413399 DOI: 10.1016/j.yrtph.2022.105167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/14/2022] [Accepted: 04/06/2022] [Indexed: 01/13/2023]
Abstract
DL-glufosinate ammonium (DL-GLF) is a registered herbicide for which a guideline Developmental Neurotoxicity (DNT) study has been conducted. Offspring effects included altered brain morphometrics, decreased body weight, and increased motor activity. Guideline DNT studies are not available for its enriched isomers L-GLF acid and L-GLF ammonium; conducting one would be time consuming, resource-intensive, and possibly redundant given the existing DL-GLF DNT. To support deciding whether to request a guideline DNT study for the L-GLF isomers, DL-GLF and the L-GLF isomers were screened using in vitro assays for network formation and neurite outgrowth. DL-GLF and L-GLF isomers were without effects in both assays. DL-GLF and L-GLF (1-100 μM) isomers increased mean firing rate of mature networks to 120-140% of baseline. In vitro toxicokinetic assessments were used to derive administered equivalent doses (AEDs) for the in vitro testing concentrations. The AED for L-GLF was ∼3X higher than the NOAEL from the DL-GLF DNT indicating that the available guideline study would be protective of potential DNT due to L-GLF exposure. Based in part on the results of these in vitro studies, EPA is not requiring L-GLF isomer guideline DNT studies, thereby providing a case study for a useful application of DNT screening assays.
Collapse
Affiliation(s)
| | | | - Anna Lowit
- Office of Pesticide Programs USEPA, Washington, DC, USA
| | - Theresa M Freudenrich
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Kathleen Wallace
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Amy Carpenter
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | - Barbara A Wetmore
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Anna Kreutz
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN, USA
| | | | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Timothy J Shafer
- Center for Computational Toxicology and Exposure, Office of Research and Development. US Environmental Protection Agency, Research Triangle Park, NC, USA.
| |
Collapse
|
9
|
Carstens KE, Carpenter AF, Martin MM, Harrill JA, Shafer TJ, Paul Friedman K. OUP accepted manuscript. Toxicol Sci 2022; 187:62-79. [PMID: 35172012 PMCID: PMC9421662 DOI: 10.1093/toxsci/kfac018] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In vivo developmental neurotoxicity (DNT) testing is resource intensive and lacks information on cellular processes affected by chemicals. To address this, DNT new approach methodologies (NAMs) are being evaluated, including: the microelectrode array neuronal network formation assay; and high-content imaging to evaluate proliferation, apoptosis, neurite outgrowth, and synaptogenesis. This work addresses 3 hypotheses: (1) a broad screening battery provides a sensitive marker of DNT bioactivity; (2) selective bioactivity (occurring at noncytotoxic concentrations) may indicate functional processes disrupted; and, (3) a subset of endpoints may optimally classify chemicals with in vivo evidence for DNT. The dataset was comprised of 92 chemicals screened in all 57 assay endpoints sourced from publicly available data, including a set of DNT NAM evaluation chemicals with putative positives (53) and negatives (13). The DNT NAM battery provides a sensitive marker of DNT bioactivity, particularly in cytotoxicity and network connectivity parameters. Hierarchical clustering suggested potency (including cytotoxicity) was important for classifying positive chemicals with high sensitivity (93%) but failed to distinguish patterns of disrupted functional processes. In contrast, clustering of selective values revealed informative patterns of differential activity but demonstrated lower sensitivity (74%). The false negatives were associated with several limitations, such as the maximal concentration tested or gaps in the biology captured by the current battery. This work demonstrates that this multi-dimensional assay suite provides a sensitive biomarker for DNT bioactivity, with selective activity providing possible insight into specific functional processes affected by chemical exposure and a basis for further research.
Collapse
Affiliation(s)
- Kelly E Carstens
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - Amy F Carpenter
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - Melissa M Martin
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Joshua A Harrill
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Timothy J Shafer
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| | - Katie Paul Friedman
- Center for Computational Toxicology and Exposure, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711, USA
| |
Collapse
|
10
|
Marable CA, Frank CL, Seim RF, Hester S, Henderson WM, Chorley B, Shafer TJ. Integrated Omic Analyses Identify Pathways and Transcriptomic Regulators Associated with Chemical Alterations of in Vitro Neural Network Formation. Toxicol Sci 2021; 186:118-133. [PMID: 34927697 DOI: 10.1093/toxsci/kfab151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Development of in vitro new approach methodologies (NAMs) has been driven by the need for developmental neurotoxicity (DNT) hazard data on thousands of chemicals. The network formation assay (NFA) characterizes DNT hazard based on changes in network formation but provides no mechanistic information. This study investigated nervous system signaling pathways and upstream physiological regulators underlying chemically-induced neural network dysfunction. Rat primary cortical neural networks grown on microelectrode arrays were exposed for 12 days in vitro (DIV) to cytosine arabinoside (CA), 5 fluorouracil (5FU), domoic acid (DA), cypermethrin (CM), deltamethrin (DM), or haloperidol (HP) as these exposures altered network formation in previous studies. RNA-seq from cells and GC/MS analysis of media extracts collected on DIV 12 provided gene expression and metabolomic identification, respectively. The integration of differentially expressed genes and metabolites for each neurotoxicant was analyzed using Ingenuity Pathway Analysis (IPA). All six compounds altered gene expression that linked to developmental disorders and neurological diseases. Other enriched canonical pathways overlapped among compounds of the same class; for example, genes and metabolites altered by both CA and 5FU exposures are enriched in axonal guidance pathways. Integrated analysis of upstream regulators was heterogeneous across compounds, but identified several transcriptomic regulators including CREB1, SOX2, NOTCH1, and PRODH. These results demonstrate that changes in network formation are accompanied by transcriptomic and metabolomic changes and that different classes of compounds produce differing responses. This approach can enhance information obtained from NAMs and contribute to the identification and development of adverse outcome pathways (AOPs) associated with DNT.
Collapse
Affiliation(s)
- Carmen A Marable
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC, 27711.,Grantee to the U.S. EPA via Oak Ridge Institute for Science and Education, Research Triangle Park, NC, 27711
| | - Christopher L Frank
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC, 27711
| | - Roland F Seim
- Grantee to the U.S. EPA via Oak Ridge Institute for Science and Education, Athens, GA.,Chemical Processes and Systems Branch, Seim, Center for Environmental Measurement and Modeling, US Environmental Protection Agency, Athens, GA, 30605
| | - Susan Hester
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC, 27711
| | - W Matthew Henderson
- Chemical Processes and Systems Branch, Seim, Center for Environmental Measurement and Modeling, US Environmental Protection Agency, Athens, GA, 30605
| | - Brian Chorley
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC, 27711
| | - Timothy J Shafer
- Rapid Assay Development Branch, Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Research Triangle Park, NC, 27711
| |
Collapse
|
11
|
Abstract
Neuroelectrophysiology is an old science, dating to the 18th century when electrical activity in nerves was discovered. Such discoveries have led to a variety of neurophysiological techniques, ranging from basic neuroscience to clinical applications. These clinical applications allow assessment of complex neurological functions such as (but not limited to) sensory perception (vision, hearing, somatosensory function), and muscle function. The ability to use similar techniques in both humans and animal models increases the ability to perform mechanistic research to investigate neurological problems. Good animal to human homology of many neurophysiological systems facilitates interpretation of data to provide cause-effect linkages to epidemiological findings. Mechanistic cellular research to screen for toxicity often includes gaps between cellular and whole animal/person neurophysiological changes, preventing understanding of the complete function of the nervous system. Building Adverse Outcome Pathways (AOPs) will allow us to begin to identify brain regions, timelines, neurotransmitters, etc. that may be Key Events (KE) in the Adverse Outcomes (AO). This requires an integrated strategy, from in vitro to in vivo (and hypothesis generation, testing, revision). Scientists need to determine intermediate levels of nervous system organization that are related to an AO and work both upstream and downstream using mechanistic approaches. Possibly more than any other organ, the brain will require networks of pathways/AOPs to allow sufficient predictive accuracy. Advancements in neurobiological techniques should be incorporated into these AOP-base neurotoxicological assessments, including interactions between many regions of the brain simultaneously. Coupled with advancements in optogenetic manipulation, complex functions of the nervous system (such as acquisition, attention, sensory perception, etc.) can be examined in real time. The integration of neurophysiological changes with changes in gene/protein expression can begin to provide the mechanistic underpinnings for biological changes. Establishment of linkages between changes in cellular physiology and those at the level of the AO will allow construction of biological pathways (AOPs) and allow development of higher throughput assays to test for changes to critical physiological circuits. To allow mechanistic/predictive toxicology of the nervous system to be protective of human populations, neuroelectrophysiology has a critical role in our future.
Collapse
Affiliation(s)
- David W Herr
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, CPHEA/ORD, U.S. Environmental Protection Agency, Washington, NC, United States
| |
Collapse
|
12
|
Capturing the third dimension in drug discovery: Spatially-resolved tools for interrogation of complex 3D cell models. Biotechnol Adv 2021; 55:107883. [PMID: 34875362 DOI: 10.1016/j.biotechadv.2021.107883] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 11/22/2021] [Accepted: 11/30/2021] [Indexed: 02/07/2023]
Abstract
Advanced three-dimensional (3D) cell models have proven to be capable of depicting architectural and microenvironmental features of several tissues. By providing data of higher physiological and pathophysiological relevance, 3D cell models have been contributing to a better understanding of human development, pathology onset and progression mechanisms, as well as for 3D cell-based assays for drug discovery. Nonetheless, the characterization and interrogation of these tissue-like structures pose major challenges on the conventional analytical methods, pushing the development of spatially-resolved technologies. Herein, we review recent advances and pioneering technologies suitable for the interrogation of multicellular 3D models, while capable of retaining biological spatial information. We focused on imaging technologies and omics tools, namely transcriptomics, proteomics and metabolomics. The advantages and shortcomings of these novel methodologies are discussed, alongside the opportunities to intertwine data from the different tools.
Collapse
|
13
|
Ishibashi Y, Odawara A, Kinoshita K, Okamura A, Shirakawa T, Suzuki I. Principal Component Analysis to Distinguish Seizure Liability of Drugs in Human iPS Cell-Derived Neurons. Toxicol Sci 2021; 184:265-275. [PMID: 34570236 DOI: 10.1093/toxsci/kfab116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Screening for drug discovery targeting the central nervous system requires the establishment of efficient and highly accurate toxicity test methods that can reduce costs and time while maintaining high throughput using the function of an in vitro neural network. In particular, an evaluation system using a human-derived neural network is desirable in terms of species difference. Despite the attention the microelectrode array (MEA) is attracting among the evaluation systems that can measure in vitro neural activity, an effective analysis method for evaluation of toxicity and mechanism of action has not yet been established. Here we established analytical parameters and multivariate analysis method capable of detecting seizure liability of drugs using MEA measurement of human iPS cell-derived neurons. Using the spike time series data of all drugs, we established periodicity as a new analytical parameter. Periodicity has facilitated the detection of responses to seizurogenic drugs, previously difficult to detect with conventional analytical parameters. By constructing a multivariate analytical method that identifies a parameter set that achieves an arbitrary condition, we found that the parameter set comprising total spikes, maximum frequency, inter maximum frequency interval, coefficient of variance of inter maximum frequency interval, and periodicity can uniformly detect the seizure liability of seizurogenic drugs with different mechanisms of action. Seizurogenic drugs were suggested to increase the regularity of the network burst in MEA measurements in human iPS cell-derived neurons.
Collapse
Affiliation(s)
- Y Ishibashi
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan
| | - A Odawara
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan
| | - K Kinoshita
- Drug Safety Research Labs, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-0841, Japan
| | - A Okamura
- Drug Safety Research Labs, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-0841, Japan
| | - T Shirakawa
- Drug Safety Research Labs, Astellas Pharma Inc, 21 Miyukigaoka, Tsukuba, Ibaraki, 305-0841, Japan
| | - I Suzuki
- Department of Electronics, Graduate School of Engineering, Tohoku Institute of Technology, 35-1 Yagiyama Kasumicho, Taihaku-ku, Sendai, Miyagi, 982-8577, Japan
| |
Collapse
|
14
|
Kharrati-Koopaee H, Ebrahimie E, Dadpasand M, Niazi A, Tian R, Esmailizadeh A. Gene network analysis to determine the effect of hypoxia-associated genes on brain damages and tumorigenesis using an avian model. J Genet Eng Biotechnol 2021; 19:100. [PMID: 34236536 PMCID: PMC8266987 DOI: 10.1186/s43141-021-00184-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/21/2021] [Indexed: 01/17/2023]
Abstract
BACKGROUND Hypoxia refers to the condition of low oxygen pressure in the atmosphere and characterization of response to hypoxia as a biological complex puzzle, is challenging. Previously, we carried out a comparative genomic study by whole genome resequencing of highland and lowland Iranian native chickens to identify genomic variants associated with hypoxia conditions. Based on our previous findings, we used chicken as a model and the identified hypoxia-associated genes were converted to human's orthologs genes to construct the informative gene network. The main goal of this study was to visualize the features of diseases due to hypoxia-associated genes by gene network analysis. RESULTS It was found that hypoxia-associated genes contained several gene networks of disorders such as Parkinson, Alzheimer, cardiomyopathy, drug toxicity, and cancers. We found that biological pathways are involved in mitochondrion dysfunctions including peroxynitrous acid production denoted in brain injuries. Lewy body and neuromelanin were reported as key symptoms in Parkinson disease. Furthermore, calmodulin, and amyloid precursor protein were detected as leader proteins in Alzheimer's diseases. Dexamethasone was reported as the candidate toxic drug under the hypoxia condition that implicates diabetes, osteoporosis, and neurotoxicity. Our results suggested DNA damages caused by the high doses of UV radiation in high-altitude conditions, were associated with breast cancer, ovarian cancer, and colorectal cancer. CONCLUSIONS Our results showed that hypoxia-associated genes were enriched in several gene networks of disorders including Parkinson, Alzheimer, cardiomyopathy, drug toxicity, and different types of cancers. Furthermore, we suggested, UV radiation and low oxygen conditions in high-altitude regions may be responsible for the variety of human diseases.
Collapse
Affiliation(s)
- Hamed Kharrati-Koopaee
- Institute of Biotechnology, Shiraz University, Shiraz, Iran.
- Department of Animal Science, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran.
| | - Esmaeil Ebrahimie
- Institute of Biotechnology, Shiraz University, Shiraz, Iran
- School of Animal and Veterinary Sciences, The University of Adelaide, Adelaide, Australia
- Genomics Research Platform, School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
| | - Mohammad Dadpasand
- Department of Animal Science, School of Agriculture, Shiraz University, Shiraz, Iran.
| | - Ali Niazi
- Institute of Biotechnology, Shiraz University, Shiraz, Iran
| | - Rugang Tian
- Institute of Animal Husbandry, Inner Mongolia Academy of Agricultural & Animal Husbandry Sciences, Hohhot, 010031, China
| | - Ali Esmailizadeh
- Department of Animal Science, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran.
| |
Collapse
|
15
|
Gerber LS, van Melis LVJ, van Kleef RGDM, de Groot A, Westerink RHS. Culture of Rat Primary Cortical Cells for Microelectrode Array (MEA) Recordings to Screen for Acute and Developmental Neurotoxicity. Curr Protoc 2021; 1:e158. [PMID: 34152700 DOI: 10.1002/cpz1.158] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Neurotoxicity testing of chemicals, drug candidates, and environmental pollutants still relies on extensive in vivo studies that are very costly, time-consuming, and ethically debated due to the large number of animals typically used. Currently, rat primary cortical cultures are widely used for in vitro neurotoxicity studies, as they closely resemble the in vitro brain with respect to the diversity of cell types, their physiological functions, and the pathological processes that they undergo. Common in vitro assays for neurotoxicity screening often focus on very target-specific endpoints such as morphological, biochemical, or electrophysiological changes, and such narrow focus can hamper translation and interpretation. Microelectrode array (MEA) recordings provide a non-invasive platform for extracellular recording of electrical activity of cultured neuronal cells, thereby enabling the evaluation of changes in neuronal (network) function as a sensitive and integrated endpoint for neurotoxicity screening. Here, we describe an in vitro approach for assessing changes in neuronal network function as a measure for neurotoxicity, using rat primary cortical cultures grown on MEAs. We provide a detailed protocol for the culture of rat primary cortical cells, and describe several experimental procedures to address acute, subchronic, and chronic exposure scenarios. We additionally describe the steps for processing and analyzing MEA and cell viability data. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Isolation and culture of rat primary cortical cells on 48-well MEA plates Support Protocol 1: Pretreatment and washing of 48-well MEA plates before first use or for re-use Support Protocol 2: Coating of 48-well MEA plates with 0.1% PEI solution Basic Protocol 2: MEA measurements during acute exposure Alternate Protocol 1: MEA measurements during subchronic exposure Alternate Protocol 2: MEA measurements during chronic exposure Support Protocol 3: Determination of cell viability after MEA experiments Basic Protocol 3: MEA data processing Basic Protocol 4: Analyzing MEA experiments after acute and subchronic exposure Alternate Protocol 3: Analyzing MEA experiments after chronic exposure.
Collapse
Affiliation(s)
- Lora-Sophie Gerber
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Lennart V J van Melis
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Aart de Groot
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| |
Collapse
|
16
|
Passaro AP, Aydin O, Saif MTA, Stice SL. Development of an objective index, neural activity score (NAS), reveals neural network ontogeny and treatment effects on microelectrode arrays. Sci Rep 2021; 11:9110. [PMID: 33907294 PMCID: PMC8079414 DOI: 10.1038/s41598-021-88675-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/16/2021] [Indexed: 02/06/2023] Open
Abstract
Microelectrode arrays (MEAs) are valuable tools for electrophysiological analysis, providing assessment of neural network health and development. Analysis can be complex, however, requiring intensive processing of large data sets consisting of many activity parameters, leading to information loss as studies subjectively report relatively few metrics in the interest of simplicity. In screening assays, many groups report simple overall activity (i.e. firing rate) but omit network connectivity changes (e.g. burst characteristics and synchrony) that may not be evident from basic parameters. Our goal was to develop an objective process to capture most of the valuable information gained from 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 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)-reflecting neural maturation. For validation, we applied NAS to studies analyzing various treatments. In all cases, NAS accurately recapitulated expected results, suggesting viability of NAS to measure network health and development. This approach may be adopted by other researchers using MEAs to analyze complicated treatment effects and multicellular interactions.
Collapse
Affiliation(s)
- Austin P. Passaro
- grid.213876.90000 0004 1936 738XRegenerative Bioscience Center, University of Georgia, Athens, GA USA ,grid.213876.90000 0004 1936 738XDivision of Neuroscience, Biomedical Health and Sciences Institute, University of Georgia, Athens, GA USA
| | - Onur Aydin
- grid.35403.310000 0004 1936 9991Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - M. Taher A. Saif
- grid.35403.310000 0004 1936 9991Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Steven L. Stice
- grid.213876.90000 0004 1936 738XRegenerative Bioscience Center, University of Georgia, Athens, GA USA ,grid.213876.90000 0004 1936 738XDivision of Neuroscience, Biomedical Health and Sciences Institute, University of Georgia, Athens, GA USA
| |
Collapse
|
17
|
Passaro AP, Stice SL. Electrophysiological Analysis of Brain Organoids: Current Approaches and Advancements. Front Neurosci 2021; 14:622137. [PMID: 33510616 PMCID: PMC7835643 DOI: 10.3389/fnins.2020.622137] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/11/2020] [Indexed: 12/23/2022] Open
Abstract
Brain organoids, or cerebral organoids, have become widely used to study the human brain in vitro. As pluripotent stem cell-derived structures capable of self-organization and recapitulation of physiological cell types and architecture, brain organoids bridge the gap between relatively simple two-dimensional human cell cultures and non-human animal models. This allows for high complexity and physiological relevance in a controlled in vitro setting, opening the door for a variety of applications including development and disease modeling and high-throughput screening. While technologies such as single cell sequencing have led to significant advances in brain organoid characterization and understanding, improved functional analysis (especially electrophysiology) is needed to realize the full potential of brain organoids. In this review, we highlight key technologies for brain organoid development and characterization, then discuss current electrophysiological methods for brain organoid analysis. While electrophysiological approaches have improved rapidly for two-dimensional cultures, only in the past several years have advances been made to overcome limitations posed by the three-dimensionality of brain organoids. Here, we review major advances in electrophysiological technologies and analytical methods with a focus on advances with applicability for brain organoid analysis.
Collapse
Affiliation(s)
- Austin P. Passaro
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States
- Division of Neuroscience, Biomedical & Health Sciences Institute, University of Georgia, Athens, GA, United States
| | - Steven L. Stice
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States
- Division of Neuroscience, Biomedical & Health Sciences Institute, University of Georgia, Athens, GA, United States
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States
| |
Collapse
|
18
|
Shafer TJ, Brown JP, Lynch B, Davila-Montero S, Wallace K, Friedman KP. Evaluation of Chemical Effects on Network Formation in Cortical Neurons Grown on Microelectrode Arrays. Toxicol Sci 2020; 169:436-455. [PMID: 30816951 DOI: 10.1093/toxsci/kfz052] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Thousands of chemicals to which humans are potentially exposed have not been evaluated for potential developmental neurotoxicity (DNT), driving efforts to develop a battery of in vitro screening approaches for DNT hazard. Here, 136 unique chemicals were evaluated for potential DNT hazard using a network formation assay (NFA) in cortical cells grown on microelectrode arrays. The effects of chemical exposure from 2 h postplating through 12 days in vitro (DIV) on network formation were evaluated at DIV 5, 7, 9, and 12, with cell viability assessed at DIV 12. Only 82 chemicals altered at least 1 network development parameter. Assay results were reproducible; 10 chemicals tested as biological replicates yielded qualitative results that were 100% concordant, with consistent potency values. Toxicological tipping points were determined for 58 chemicals and were similar to or lower than the lowest 50% effect concentrations (EC50) for all parameters. When EC50 and tipping point values from the NFA were compared to the range of potencies observed in ToxCast assays, the NFA EC50 values were less than the lower quartile for ToxCast assay potencies for a subset of chemicals, many of which are acutely neurotoxic in vivo. For 13 chemicals with available in vivo DNT data, estimated administered equivalent doses based on NFA results were similar to or lower than administered doses in vivo. Collectively, these results indicate that the NFA is sensitive to chemicals acting on nervous system function and will be a valuable contribution to an in vitro DNT screening battery.
Collapse
Affiliation(s)
- Timothy J Shafer
- Integrated Systems Toxicology Division, NHEERL, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Jasmine P Brown
- Integrated Systems Toxicology Division, NHEERL, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711.,Graduate Program in Public Health, University of Michigan, Ann Arbor, MI
| | - Brittany Lynch
- Tandon School of Engineering, New York University, Brooklyn, New York 11201
| | - Sylmarie Davila-Montero
- Department of Electrical and Computer Engineering, Michigan State University, E. Lansing, Michigan 48824
| | - Kathleen Wallace
- Integrated Systems Toxicology Division, NHEERL, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Katie Paul Friedman
- National Center for Computational Toxicology, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| |
Collapse
|
19
|
Tukker AM, Bouwman LMS, van Kleef RGDM, Hendriks HS, Legler J, Westerink RHS. Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) acutely affect human α 1β 2γ 2L GABA A receptor and spontaneous neuronal network function in vitro. Sci Rep 2020; 10:5311. [PMID: 32210279 PMCID: PMC7093421 DOI: 10.1038/s41598-020-62152-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/04/2020] [Indexed: 11/28/2022] Open
Abstract
Concerns about the neurotoxic potential of polyfluoroalkyl substances (PFAS) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) increase, although their neurotoxic mechanisms of action remain debated. Considering the importance of the GABAA receptor in neuronal function, we investigated acute effects of PFAS on this receptor and on spontaneous neuronal network activity. PFOS (Lowest Observed Effect Concentration (LOEC) 0.1 µM) and PFOA (LOEC 1 µM) inhibited the GABA-evoked current and acted as non-competitive human GABAA receptor antagonists. Network activity of rat primary cortical cultures increased following exposure to PFOS (LOEC 100 µM). However, exposure of networks of human induced pluripotent stem cell (hiPSC)-derived neurons decreased neuronal activity. The higher sensitivity of the α1β2γ2L GABAA receptor for PFAS as compared to neuronal networks suggests that PFAS have additional mechanisms of action, or that compensatory mechanisms are at play. Differences between rodent and hiPSC-derived neuronal networks highlight the importance of proper model composition. LOECs for PFAS on GABAA receptor and neuronal activity reported here are within or below the range found in blood levels of occupationally exposed humans. For PFOS, LOECs are even within the range found in human serum and plasma of the general population, suggesting a clear neurotoxic risk.
Collapse
Affiliation(s)
- Anke M Tukker
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Lianne M S Bouwman
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Juliette Legler
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508, TD, Utrecht, The Netherlands.
| |
Collapse
|
20
|
Gao F, Gao K, He C, Liu M, Hu Y, Ying K, Wan H, Wang P. [ In vitro pathological model of Alzheimer's disease based on neuronal network chip and its real-time dynamic analysis]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 2019; 36:893-901. [PMID: 31875361 PMCID: PMC9935160 DOI: 10.7507/1001-5515.201902014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Indexed: 11/03/2022]
Abstract
Alzheimer's disease (AD) is a chronic central neurodegenerative disease. The pathological features of AD are the extracellular deposition of senile plaques formed by amyloid-β oligomers (AβOs) and the intracellular accumulation of neurofibrillary tangles formed by hyperphosphorylated tau protein. In this paper, an in vitro pathological model of AD based on neuronal network chip and its real-time dynamic analysis were presented. The hippocampal neuronal network was cultured on the microelectrode array (MEA) chip and induced by AβOs as an AD model in vitro to simultaneously record two firing patterns from the interneurons and pyramidal neurons. The spatial firing patterns mapping and cross-correlation between channels were performed to validate the degeneration of neuronal network connectivity. This biosensor enabled the detection of the AβOs toxicity responses, and the identification of connectivity and interactions between neuronal networks, which can be a novel technique in the research of AD pathological model in vitro.
Collapse
Affiliation(s)
- Fan Gao
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou 310027, P.R.China
| | - Keqiang Gao
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou 310027, P.R.China
| | - Chuanjiang He
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou 310027, P.R.China
| | - Mengxue Liu
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou 310027, P.R.China
| | - Yanjie Hu
- Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310027, P.R.China
| | - Kejing Ying
- Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310027, P.R.China
| | - Hao Wan
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou 310027, P.R.China
| | - Ping Wang
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou 310027,
| |
Collapse
|
21
|
Wang Y, Graham ES, Unsworth CP. First observations of spontaneous bursting in human hNT neurons with a customised neural chip platform. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab4b24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
22
|
Fritsche E, Barenys M, Klose J, Masjosthusmann S, Nimtz L, Schmuck M, Wuttke S, Tigges J. Current Availability of Stem Cell-Based In Vitro Methods for Developmental Neurotoxicity (DNT) Testing. Toxicol Sci 2019; 165:21-30. [PMID: 29982830 DOI: 10.1093/toxsci/kfy178] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
There is evidence that chemical exposure during development can cause irreversible impairments of the human developing nervous system. Therefore, testing compounds for their developmentally neurotoxic potential has high priority for different stakeholders: academia, industry, and regulatory bodies. Due to the resource-intensity of current developmental neurotoxicity (DNT) in vivo guidelines, alternative methods that are scientifically valid and have a high predictivity for humans are especially desired by regulators. Here, we review availability of stem-/progenitor cell-based in vitro methods for DNT evaluation that is based on the concept of neurodevelopmental process assessment. These test methods are assembled into a DNT in vitro testing battery. Gaps in this testing battery addressing research needs are also pointed out.
Collapse
Affiliation(s)
| | - Marta Barenys
- IUF - Leibniz Research Institute for Environmental Medicine 40225, Düsseldorf, Germany
| | - Jördis Klose
- IUF - Leibniz Research Institute for Environmental Medicine 40225, Düsseldorf, Germany
| | - Stefan Masjosthusmann
- IUF - Leibniz Research Institute for Environmental Medicine 40225, Düsseldorf, Germany
| | - Laura Nimtz
- IUF - Leibniz Research Institute for Environmental Medicine 40225, Düsseldorf, Germany
| | - Martin Schmuck
- IUF - Leibniz Research Institute for Environmental Medicine 40225, Düsseldorf, Germany
| | - Saskia Wuttke
- IUF - Leibniz Research Institute for Environmental Medicine 40225, Düsseldorf, Germany
| | - Julia Tigges
- IUF - Leibniz Research Institute for Environmental Medicine 40225, Düsseldorf, Germany
| |
Collapse
|
23
|
Fritsche E, Barenys M, Klose J, Masjosthusmann S, Nimtz L, Schmuck M, Wuttke S, Tigges J. Development of the Concept for Stem Cell-Based Developmental Neurotoxicity Evaluation. Toxicol Sci 2019; 165:14-20. [PMID: 29982725 DOI: 10.1093/toxsci/kfy175] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Human brain development consists of a series of complex spatiotemporal processes that if disturbed by chemical exposure causes irreversible impairments of the nervous system. To evaluate a chemical disturbance in an alternative assay, the concept evolved that the complex procedure of brain development can be disassembled into several neurodevelopmental endpoints which can be represented by a combination of different alternative assays. In this review article, we provide a scientific rationale for the neurodevelopmental endpoints that are currently chosen to establish assays with human stem/and progenitor cells. Assays covering these major neurodevelopmental endpoints are thought to assemble as building blocks of a DNT testing battery.
Collapse
Affiliation(s)
- Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany.,Heinrich Heine University, 40225 Düsseldorf, Germany
| | | | - Jördis Klose
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Stefan Masjosthusmann
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Laura Nimtz
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Martin Schmuck
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Saskia Wuttke
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Julia Tigges
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| |
Collapse
|
24
|
Active High-Density Electrode Arrays: Technology and Applications in Neuronal Cell Cultures. ADVANCES IN NEUROBIOLOGY 2019. [PMID: 31073940 DOI: 10.1007/978-3-030-11135-9_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Active high-density electrode arrays realized with complementary metal-oxide-semiconductor (CMOS) technology provide electrophysiological recordings from several thousands of closely spaced microelectrodes. This has drastically advanced the spatiotemporal recording resolution of conventional multielectrode arrays (MEAs). Thus, today's electrophysiology in neuronal cultures can exploit label-free electrical readouts from a large number of single neurons within the same network. This provides advanced capabilities to investigate the properties of self-assembling neuronal networks, to advance studies on neurotoxicity and neurodevelopmental alterations associated with human brain diseases, and to develop cell culture models for testing drug- or cell-based strategies for therapies.Here, after introducing the reader to this neurotechnology, we summarize the results of different recent studies demonstrating the potential of active high-density electrode arrays for experimental applications. We also discuss ongoing and possible future research directions that might allow for moving these platforms forward for screening applications.
Collapse
|
25
|
Bradley JA, Luithardt HH, Metea MR, Strock CJ. In Vitro Screening for Seizure Liability Using Microelectrode Array Technology. Toxicol Sci 2019; 163:240-253. [PMID: 29432603 DOI: 10.1093/toxsci/kfy029] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Drug-induced seizure liabilities produce significant compound attrition during drug discovery. Currently available in vitro cytotoxicity assays cannot predict all toxicity mechanisms due to the failure of these assays to predict sublethal target-specific electrophysiological liabilities. Identification of seizurogenic and other electrophysiological effects at early stages of the drug development process is important to ensure that safe candidate compounds can be developed while chemical design is taking place, long before these liabilities are discovered in costly preclinical in vivo studies. The development of a high throughput and reliable in vitro assay to screen compounds for seizure liabilities would de-risk compounds significantly earlier in the drug discovery process and with greater dependability. Here we describe a method for screening compounds that utilizes rat cortical neurons plated onto multiwell microelectrode array plates to identify compounds that cause neurophysiological disruptions. Changes in 12 electrophysiological parameters (spike train descriptors) were measured after application of known seizurogenic compounds and the response pattern was mapped relative to negative controls, vehicle control and neurotoxic controls. Twenty chemicals with a variety of therapeutic indications and targets, including GABAA antagonists, glycine receptor antagonists, ion channel blockers, muscarinic agonist, δ-opioid receptor agonist, dopaminergic D2/adrenergic receptor blocker and nonsteroidal anti-inflammatory drugs, were tested to assess this system. Sixteen of the seventeen seizurogenic/neurotoxic compounds tested positive for seizure liability or neurotoxicity, moreover, different endpoint response patterns for firing rate, burst characteristics and synchrony that distinguished the chemicals into groups relating to target and seizurogenic response emerged from the data. The negative and vehicle control compounds had no effect on neural activity. In conclusion, the multiwell microelectrode array platform using cryopreserved rat cortical neurons is a highly effective high throughput method for reliably screening seizure liabilities within an early de-risking drug development paradigm.
Collapse
Affiliation(s)
| | | | - Monica R Metea
- Cyprotex US, LLC, An Evotec Company, Watertown, Massachusetts
| | | |
Collapse
|
26
|
Shafer TJ. Application of Microelectrode Array Approaches to Neurotoxicity Testing and Screening. ADVANCES IN NEUROBIOLOGY 2019; 22:275-297. [PMID: 31073941 DOI: 10.1007/978-3-030-11135-9_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Neurotoxicity can be defined by the ability of a drug or chemical to alter the physiology, biochemistry, or structure of the nervous system in a manner that may negatively impact the health or function of the individual. Electrophysiological approaches have been utilized to study the mechanisms underlying neurotoxic actions of drugs and chemicals for over 50 years, and in more recent decades, high-throughput patch-clamp approaches have been utilized by the pharmaceutical industry for drug development. The use of microelectrode array recordings to study neural network electrophysiology is a relatively newer approach, with commercially available systems becoming available only in the early 2000s. However, MEAs have been rapidly adopted as a useful approach for neurotoxicity testing. In this chapter, I will review the use of MEA approaches as they have been applied to the field of neurotoxicity testing, especially as they have been applied to the need to screen large numbers of chemicals for neurotoxicity and developmental neurotoxicity. In addition, I will also identify challenges for the field that when addressed will improve the utility of MEA approaches for toxicity testing.
Collapse
Affiliation(s)
- Timothy J Shafer
- Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory (NHEERL), US EPA, Research Triangle Park, NC, USA.
| |
Collapse
|
27
|
Seidel D, Jahnke HG, Englich B, Girard M, Robitzki AA. In vitro field potential monitoring on a multi-microelectrode array for the electrophysiological long-term screening of neural stem cell maturation. Analyst 2018; 142:1929-1937. [PMID: 28484750 DOI: 10.1039/c6an02713j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Due to the lack of appropriate cell models as well as automated electrophysiology monitoring technologies, the standardized identification of neurotoxic or protective effects in vitro remains a major problem in today's pharmaceutical ingredient development. Over the past few years, in vivo-like human pluripotent stem cell-derived neuronal networks have turned out to be a promising physiological cell source, if the establishment of robust and time-saving functional maturation strategies based on stable and expandable neural progenitor populations can be achieved. Here, we describe a multi-microelectrode array (MMEA)-based bioelectronics platform that was optimized for long-term electrophysiological activity monitoring of neuronal networks via field potential measurements. Differentiation of small molecule-based neuronal progenitors on MMEAs led to functional neurons within 15 days. More strikingly, these functional neuronal cultures could remain electrophysiologically stable on the MMEAs for more than four weeks. The observed electrophysiological properties correlated with the expression of typical neuron subtype markers and were further validated by specific neurotransmitter applications. With our established monitoring platform, we could show for the first time the long-term stability of the neural stem cell-like progenitor population to differentiate to electrophysiologically active dopaminergic neuronal networks for more than 80 passages. In conclusion, we provide a comprehensive long-term stable field potential monitoring platform based on stem cell-derived human neuronal networks that can be automated and up-scaled for standardized high-content screening applications e.g. in the field of neurotoxic and neuroprotective therapeutics identification.
Collapse
Affiliation(s)
- Diana Seidel
- Centre for Biotechnology and Biomedicine (BBZ), University of Leipzig, Division of Molecular Biological-Biochemical Processing Technology, D-04103 Leipzig, Germany.
| | - Heinz-Georg Jahnke
- Centre for Biotechnology and Biomedicine (BBZ), University of Leipzig, Division of Molecular Biological-Biochemical Processing Technology, D-04103 Leipzig, Germany.
| | - Beate Englich
- Centre for Biotechnology and Biomedicine (BBZ), University of Leipzig, Division of Molecular Biological-Biochemical Processing Technology, D-04103 Leipzig, Germany.
| | - Mathilde Girard
- CECS, I-STEM, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, Genopole Campus 1, 5 rue Henri Desbruères, 91030 Evry Cedex, France
| | - Andrea A Robitzki
- Centre for Biotechnology and Biomedicine (BBZ), University of Leipzig, Division of Molecular Biological-Biochemical Processing Technology, D-04103 Leipzig, Germany.
| |
Collapse
|
28
|
Frank CL, Brown JP, Wallace K, Wambaugh JF, Shah I, Shafer TJ. Defining toxicological tipping points in neuronal network development. Toxicol Appl Pharmacol 2018; 354:81-93. [DOI: 10.1016/j.taap.2018.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/22/2018] [Indexed: 12/18/2022]
|
29
|
Bal-Price A, Hogberg HT, Crofton KM, Daneshian M, FitzGerald RE, Fritsche E, Heinonen T, Hougaard Bennekou S, Klima S, Piersma AH, Sachana M, Shafer TJ, Terron A, Monnet-Tschudi F, Viviani B, Waldmann T, Westerink RHS, Wilks MF, Witters H, Zurich MG, Leist M. Recommendation on test readiness criteria for new approach methods in toxicology: Exemplified for developmental neurotoxicity. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2018; 35:306-352. [PMID: 29485663 DOI: 10.14573/altex.1712081] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/29/2018] [Indexed: 01/06/2023]
Abstract
Multiple non-animal-based test methods have never been formally validated. In order to use such new approach methods (NAMs) in a regulatory context, criteria to define their readiness are necessary. The field of developmental neurotoxicity (DNT) testing is used to exemplify the application of readiness criteria. The costs and number of untested chemicals are overwhelming for in vivo DNT testing. Thus, there is a need for inexpensive, high-throughput NAMs, to obtain initial information on potential hazards, and to allow prioritization for further testing. A background on the regulatory and scientific status of DNT testing is provided showing different types of test readiness levels, depending on the intended use of data from NAMs. Readiness criteria, compiled during a stakeholder workshop, uniting scientists from academia, industry and regulatory authorities are presented. An important step beyond the listing of criteria, was the suggestion for a preliminary scoring scheme. On this basis a (semi)-quantitative analysis process was assembled on test readiness of 17 NAMs with respect to various uses (e.g. prioritization/screening, risk assessment). The scoring results suggest that several assays are currently at high readiness levels. Therefore, suggestions are made on how DNT NAMs may be assembled into an integrated approach to testing and assessment (IATA). In parallel, the testing state in these assays was compiled for more than 1000 compounds. Finally, a vision is presented on how further NAM development may be guided by knowledge of signaling pathways necessary for brain development, DNT pathophysiology, and relevant adverse outcome pathways (AOP).
Collapse
Affiliation(s)
- Anna Bal-Price
- European Commission, Joint Research Centre (EC JRC), Ispra (VA), Italy
| | - Helena T Hogberg
- Center for Alternatives to Animal Testing (CAAT), Johns Hopkins University, Baltimore, MD, USA
| | - Kevin M Crofton
- National Centre for Computational Toxicology, US EPA, RTP, Washington, NC, USA
| | - Mardas Daneshian
- Center for Alternatives to Animal Testing, CAAT-Europe, University of Konstanz, Konstanz, Germany
| | - Rex E FitzGerald
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland
| | - Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine & Heinrich-Heine-University, Düsseldorf, Germany
| | - Tuula Heinonen
- Finnish Centre for Alternative Methods (FICAM), University of Tampere, Tampere, Finland
| | | | - Stefanie Klima
- In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Aldert H Piersma
- RIVM, National Institute for Public Health and the Environment, Bilthoven, and Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Magdalini Sachana
- Organisation for Economic Co-operation and Development (OECD), Paris, France
| | - Timothy J Shafer
- National Centre for Computational Toxicology, US EPA, RTP, Washington, NC, USA
| | | | - Florianne Monnet-Tschudi
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland.,Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Barbara Viviani
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Italy
| | - Tanja Waldmann
- In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Remco H S Westerink
- Neurotoxicology Research Group, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Martin F Wilks
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland
| | - Hilda Witters
- VITO, Flemish Institute for Technological Research, Unit Environmental Risk and Health, Mol, Belgium
| | - Marie-Gabrielle Zurich
- Swiss Centre for Human Applied Toxicology, SCAHT, University of Basle, Switzerland.,Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Marcel Leist
- Center for Alternatives to Animal Testing, CAAT-Europe, University of Konstanz, Konstanz, Germany.,In vitro Toxicology and Biomedicine, Department of Biology, University of Konstanz, Konstanz, Germany
| |
Collapse
|
30
|
Strickland JD, Martin MT, Richard AM, Houck KA, Shafer TJ. Screening the ToxCast phase II libraries for alterations in network function using cortical neurons grown on multi-well microelectrode array (mwMEA) plates. Arch Toxicol 2018; 92:487-500. [PMID: 28766123 PMCID: PMC6438628 DOI: 10.1007/s00204-017-2035-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 07/12/2017] [Indexed: 12/12/2022]
Abstract
Methods are needed for rapid screening of environmental compounds for neurotoxicity, particularly ones that assess function. To demonstrate the utility of microelectrode array (MEA)-based approaches as a rapid neurotoxicity screening tool, 1055 chemicals from EPA's phase II ToxCast library were evaluated for effects on neural function and cell health. Primary cortical networks were grown on multi-well microelectrode array (mwMEA) plates. On day in vitro 13, baseline activity (40 min) was recorded prior to exposure to each compound (40 µM). Changes in spontaneous network activity [mean firing rate (MFR)] and cell viability (lactate dehydrogenase and CellTiter Blue) were assessed within the same well following compound exposure. Following exposure, 326 compounds altered (increased or decreased) normalized MFR beyond hit thresholds based on 2× the median absolute deviation of DMSO-treated wells. Pharmaceuticals, pesticides, fungicides, chemical intermediates, and herbicides accounted for 86% of the hits. Further, changes in MFR occurred in the absence of cytotoxicity, as only eight compounds decreased cell viability. ToxPrint chemotype analysis identified several structural domains (e.g., biphenyls and alkyl phenols) significantly enriched with MEA actives relative to the total test set. The top 5 enriched ToxPrint chemotypes were represented in 26% of the MEA hits, whereas the top 11 ToxPrints were represented in 34% of MEA hits. These results demonstrate that large-scale functional screening using neural networks on MEAs can fill a critical gap in assessment of neurotoxicity potential in ToxCast assay results. Further, a data-mining approach identified ToxPrint chemotypes enriched in the MEA-hit subset, which define initial structure-activity relationship inferences, establish potential mechanistic associations to other ToxCast assay endpoints, and provide working hypotheses for future studies.
Collapse
Affiliation(s)
- Jenna D Strickland
- Axion Biosystems, Atlanta, GA, USA
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| | - Matthew T Martin
- National Center for Computational Toxicology, U.S. Environmental Protection Agency, MD D143-02, Research Triangle Park, NC, 27711, USA
- Pfizer Inc, Groton, CT, USA
| | - Ann M Richard
- National Center for Computational Toxicology, U.S. Environmental Protection Agency, MD D143-02, Research Triangle Park, NC, 27711, USA
| | - Keith A Houck
- National Center for Computational Toxicology, U.S. Environmental Protection Agency, MD D143-02, Research Triangle Park, NC, 27711, USA
| | - Timothy J Shafer
- Integrated Systems Toxicology Division, U.S. Environmental Protection Agency, MD105-05, Research Triangle Park, NC, 27711, USA.
| |
Collapse
|
31
|
Abstract
Neurite outgrowth, one of the underlying cellular processes that defines the development and functionality of the mammalian nervous system, is also a sensitive indicator of neuronal cell health. From screening libraries of putative neurotherapeutic compounds to analyzing the millions of environmental pollutants for which we have inadequate neurotoxicity safety data, the large volume of chemical compounds that require evaluation is a major obstacle for manual imaging and analysis methods. In this context, high-content analysis (HCA) has emerged as a sensitive and accurate method for detecting changes in neuronal cell morphology within a format applicable to screening large chemical libraries. Advances in HCA technologies have enabled the automated imaging and quantitative analysis of neurite outgrowth morphology within a 96-well plate in less than 5 min. Traditionally, neurite outgrowth assessment has been conducted on immortalized cell lines such as pheochromocytoma (PC-12) cells that differentiate into neuron-like cells upon culture with nerve growth factor. Unfortunately, they do not retain all the in vivo characteristics of physiological neuronal tissue, including lack of synapse formation. As researchers refine neurite outgrowth quantitative analysis using HCA, an emerging question is how to quantify this biology in more complex models that more faithfully recapitulate in vivo environments. Primary neurons provide several benefits relative to neuronal cell lines, including the elaboration of axons from secondary dendrites and formation of both pre- and postsynaptic junctions. This chapter reviews techniques for evaluating neurite outgrowth using the ArrayScan HCA platform within a model system of primary cultures of rodent cerebellar granule cells.
Collapse
|
32
|
Su L, Yimaer A, Wei X, Xu Z, Chen G. The effects of 50 Hz magnetic field exposure on DNA damage and cellular functions in various neurogenic cells. JOURNAL OF RADIATION RESEARCH 2017; 58:474-486. [PMID: 28369556 PMCID: PMC5570089 DOI: 10.1093/jrr/rrx012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Indexed: 05/15/2023]
Abstract
Epidemiological studies have indicated a possible association between extremely low-frequency magnetic field (ELF-MF) exposure and the risk of nervous system diseases. However, laboratory studies have not provided consistent results for clarifying this association, despite many years of studies. In this study, we have systematically investigated the effects of 50 Hz MF exposure on DNA damage and cellular functions in both neurogenic tumor cell lines (U251, A172, SH-SY5Y) and primary cultured neurogenic cells from rats (astrocytes, microglia, cortical neurons). The results showed that exposure to a 50 Hz MF at 2.0 mT for up to 24 h did not influence γH2AX foci formation (an early marker of DNA double-strand breaks) in any of six different neurogenic cells. Exposure to a 50 Hz MF did not affect cell cycle progression, cell proliferation or cell viability in neurogenic tumor U251, A172 or SH-SY5Y cells. Furthermore, the MF exposure for 24 h did not significantly affect the secretion of cytokines (TNF-α, IL-6 or IL-1β) in astrocytes or microglia, or the phagocytic activity of microglia. In addition, MF exposure for 1 h per day did not significantly influence expression levels of microtubule-associated protein tau, microtubule-associated protein 2, postsynaptic density 95 or gephyrin in cortical neurons, indicating an absence of effects of MF exposure on the development of cortical neurons. In conclusion, our data suggest that exposure to a 50 Hz MF at 2.0 mT did not elicit DNA damage effects or abnormal cellular functions in the neurogenic cells studied.
Collapse
Affiliation(s)
- Liling Su
- Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China
- Department of Clinical Medicine, Jiangxi Medical College, 399 Zhimi Road, Shangrao 331000, China
| | - Aziguli Yimaer
- Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Xiaoxia Wei
- Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Zhengping Xu
- Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China
- Institute of Environmental Health, Zhejiang University School of Public Health, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Guangdi Chen
- Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China
- Institute of Environmental Health, Zhejiang University School of Public Health, 866 Yuhangtang Road, Hangzhou 310058, China
- Corresponding author. Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou 310058, China. Tel: +86-571-88208169; Fax: +86-571-88208163;
| |
Collapse
|
33
|
Amin H, Nieus T, Lonardoni D, Maccione A, Berdondini L. High-resolution bioelectrical imaging of Aβ-induced network dysfunction on CMOS-MEAs for neurotoxicity and rescue studies. Sci Rep 2017; 7:2460. [PMID: 28550283 PMCID: PMC5446416 DOI: 10.1038/s41598-017-02635-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 05/03/2017] [Indexed: 11/20/2022] Open
Abstract
Neurotoxicity and the accumulation of extracellular amyloid-beta1–42 (Aβ) peptides are associated with the development of Alzheimer’s disease (AD) and correlate with neuronal activity and network dysfunctions, ultimately leading to cellular death. However, research on neurodegenerative diseases is hampered by the paucity of reliable readouts and experimental models to study such functional decline from an early onset and to test rescue strategies within networks at cellular resolution. To overcome this important obstacle, we demonstrate a simple yet powerful in vitro AD model based on a rat hippocampal cell culture system that exploits large-scale neuronal recordings from 4096-electrodes on CMOS-chips for electrophysiological quantifications. This model allows us to monitor network activity changes at the cellular level and to uniquely uncover the early activity-dependent deterioration induced by Aβ-neurotoxicity. We also demonstrate the potential of this in vitro model to test a plausible hypothesis underlying the Aβ-neurotoxicity and to assay potential therapeutic approaches. Specifically, by quantifying N-methyl D-aspartate (NMDA) concentration-dependent effects in comparison with low-concentration allogenic-Aβ, we confirm the role of extrasynaptic-NMDA receptors activation that may contribute to Aβ-neurotoxicity. Finally, we assess the potential rescue of neural stem cells (NSCs) and of two pharmacotherapies, memantine and saffron, for reversing Aβ-neurotoxicity and rescuing network-wide firing.
Collapse
Affiliation(s)
- Hayder Amin
- Nets3 Laboratory, Departement of Neuroscience & Brain Technologies (NBT), Fondazione Istituto Italiano di Tecnologia (IIT), via morego 30, 16163, Genova, Italy.
| | - Thierry Nieus
- Nets3 Laboratory, Departement of Neuroscience & Brain Technologies (NBT), Fondazione Istituto Italiano di Tecnologia (IIT), via morego 30, 16163, Genova, Italy
| | - Davide Lonardoni
- Nets3 Laboratory, Departement of Neuroscience & Brain Technologies (NBT), Fondazione Istituto Italiano di Tecnologia (IIT), via morego 30, 16163, Genova, Italy
| | - Alessandro Maccione
- Nets3 Laboratory, Departement of Neuroscience & Brain Technologies (NBT), Fondazione Istituto Italiano di Tecnologia (IIT), via morego 30, 16163, Genova, Italy
| | - Luca Berdondini
- Nets3 Laboratory, Departement of Neuroscience & Brain Technologies (NBT), Fondazione Istituto Italiano di Tecnologia (IIT), via morego 30, 16163, Genova, Italy
| |
Collapse
|
34
|
Chen H, Judkins J, Thomas C, Wu M, Khoury L, Benjamin CG, Pacione D, Golfinos JG, Kumthekar P, Ghamsari F, Chen L, Lein P, Chetkovich DM, Snuderl M, Horbinski C. Mutant IDH1 and seizures in patients with glioma. Neurology 2017; 88:1805-1813. [PMID: 28404805 DOI: 10.1212/wnl.0000000000003911] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/13/2017] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Because the d-2-hydroxyglutarate (D2HG) product of mutant isocitrate dehydrogenase 1 (IDH1mut) is released by tumor cells into the microenvironment and is structurally similar to the excitatory neurotransmitter glutamate, we sought to determine whether IDH1mut increases the risk of seizures in patients with glioma, and whether D2HG increases the electrical activity of neurons. METHODS Three WHO grade II-IV glioma cohorts from separate institutions (total N = 712) were retrospectively assessed for the presence of preoperative seizures and tumor location, WHO grade, 1p/19q codeletion, and IDH1mut status. Rat cortical neurons were grown on microelectrode arrays, and their electrical activity was measured before and after treatment with exogenous D2HG, in the presence or absence of the selective NMDA antagonist, AP5. RESULTS Preoperative seizures were observed in 18%-34% of IDH1 wild-type (IDH1wt) patients and in 59%-74% of IDH1mut patients (p < 0.001). Multivariable analysis, including WHO grade, 1p/19q codeletion, and temporal lobe location, showed that IDH1mut was an independent correlate with seizures (odds ratio 2.5, 95% confidence interval 1.6-3.9, p < 0.001). Exogenous D2HG increased the firing rate of cultured rat cortical neurons 4- to 6-fold, but was completely blocked by AP5. CONCLUSIONS The D2HG product of IDH1mut may increase neuronal activity by mimicking the activity of glutamate on the NMDA receptor, and IDH1mut gliomas are more likely to cause seizures in patients. This has rapid translational implications for the personalized management of tumor-associated epilepsy, as targeted IDH1mut inhibitors may improve antiepileptic therapy in patients with IDH1mut gliomas.
Collapse
Affiliation(s)
- Hao Chen
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Jonathon Judkins
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Cheddhi Thomas
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Meijing Wu
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Laith Khoury
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Carolina G Benjamin
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Donato Pacione
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - John G Golfinos
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Priya Kumthekar
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Farhad Ghamsari
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Li Chen
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Pamela Lein
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Dane M Chetkovich
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Matija Snuderl
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington
| | - Craig Horbinski
- From the University of California, Davis (H.C., P.L.), CA; Departments of Neurosurgery (M.W., C.H.), Neurology (L.C., D.M.C.), Physiology (D.M.C.), and Pathology (C.H.), Feinberg School of Medicine (J.J., F.G.), Northwestern University, Chicago, IL; Departments of Pathology (C.T., M.S.) and Neurosurgery (C.G.B., D.P., J.G.G.), Langone School of Medicine, New York University, New York; and Departments of Neurosurgery (L.K.) and Cancer Biostatistics (P.K.), University of Kentucky, Lexington.
| |
Collapse
|
35
|
Kasteel EEJ, Westerink RHS. Comparison of the acute inhibitory effects of Tetrodotoxin (TTX) in rat and human neuronal networks for risk assessment purposes. Toxicol Lett 2017; 270:12-16. [PMID: 28192153 DOI: 10.1016/j.toxlet.2017.02.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 11/29/2022]
Abstract
Tetrodotoxin (TTX) is an extremely toxic marine neurotoxin. TTX inhibits voltage-gated sodium channels, resulting in a potentially lethal inhibition of neurotransmission. Despite numerous intoxications in Asia and Europe, limited (human) toxicological data are available for TTX. Additionally, the degree of interspecies differences for TTX is not well established, hampering the use of available (animal) data for human risk assessment and establishing regulatory limits for TTX concentrations in (shell)fish. We therefore used micro-electrode array (MEA) recordings as an integrated measure of neurotransmission to demonstrate that TTX inhibits neuronal electrical activity in both primary rat cortical cultures and human-induced pluripotent stem cell (hIPSC)-derived iCell® neurons in co-culture with hIPSC-derived iCell® astrocytes, with IC50 values of 7 and 10nM, respectively. From these data combined with LD50 values and IC50 concentrations of voltage-gated sodium channels derived from literature it can be concluded that interspecies differences are limited for TTX. Consequently, we used experimental animal data to derive a human acute reference dose of 1.33μg/kg body weight, which corresponds to maximum concentration of TTX in shellfish of 200μg/kg.
Collapse
Affiliation(s)
- Emma E J Kasteel
- Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Division Toxicology, Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands.
| |
Collapse
|
36
|
Lee S, Yoon J, Choi M, Choi C. Induction of neuronal activation by femtosecond-pulsed laser irradiation and its potential application for amyloid-β-induced toxicity assessment. JOURNAL OF BIOPHOTONICS 2017; 10:311-319. [PMID: 27090065 DOI: 10.1002/jbio.201600004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 03/13/2016] [Accepted: 03/15/2016] [Indexed: 06/05/2023]
Abstract
Manipulating neural activity is crucial for studying the neural connectivity and the pathophysiology of neurodegenerative disease. Among various techniques for neural activation, direct optical stimulation method with femtosecond-pulsed laser is simple and can be specifically applied on a single neuron. Brief irradiation of femtosecond laser pulses on a neuron elevates intracellular calcium, and it propagates to adjacent neurons. However, the mechanisms of laser-induced neural activation are still unclear. In this report, we have elucidated the mechanism of laser-induced neural activation which could be mediated by superoxide, specifically blocked by diphenyleneiodonium chloride, and depletion in intracellular calcium storage. Furthermore, we also showed that the propagation of calcium initiated by laser stimulation is dependent on the presence of extracellular calcium as well as electrical and chemical synapses. We verified the applicability of such mechanism for the assessment of neuronal functionality, by measuring calcium elevation, intracellular calcium propagation, ROS increase, and performing cell death assay in vehicle and Aβ-treated neurons. This work suggests promising applications of the potential for implementing such laser-induced neural activation for rapid and reliable drug screening.
Collapse
Affiliation(s)
- Seunghee Lee
- Department of Bio and Brain Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- KAIST Institute for Optical Science and Technology, KAIST, Daejeon, Korea
| | - Jonghee Yoon
- KAIST Institute for Optical Science and Technology, KAIST, Daejeon, Korea
- Department of Physics, KAIST, Daejeon, Korea
| | - Myunghwan Choi
- Department of Global Biomedical Engineering, Sungkyunkwan University, Suwon, Korea
| | - Chulhee Choi
- Department of Bio and Brain Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Korea
- Department of Physics, KAIST, Daejeon, Korea
- KAIST Institute for the BioCentury, KAIST, Daejeon, Korea
| |
Collapse
|
37
|
Brown JP, Lynch BS, Curry-Chisolm IM, Shafer TJ, Strickland JD. Assaying Spontaneous Network Activity and Cellular Viability Using Multi-well Microelectrode Arrays. Methods Mol Biol 2017; 1601:153-170. [PMID: 28470525 DOI: 10.1007/978-1-4939-6960-9_13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Microelectrode array (MEA) technology is a neurophysiological method that allows for the spontaneous measure of activity in neural cultures and determination of drug and chemical effects thereon. Recent introduction of multi-well MEA (mwMEA) formats have dramatically increased the throughput of this technology, allowing more efficient compound screening. Rapid characterization of compounds for neuroactivity or neurotoxicity hazard evaluation following acute, chronic, or developmental exposures ideally would also consider compound effects on cell health, and to do so in the same well requires a multiplexed approach. Procedures describing the multiplexed method to acute and developmental screening are described in this chapter.
Collapse
Affiliation(s)
- Jasmine P Brown
- Integrated Systems Toxicology Division, NHEERL, US EPA, MD105-05, Research Triangle Park, NC, 27711, USA
| | - Brittany S Lynch
- Integrated Systems Toxicology Division, NHEERL, US EPA, MD105-05, Research Triangle Park, NC, 27711, USA
| | - Itaevia M Curry-Chisolm
- Integrated Systems Toxicology Division, NHEERL, US EPA, MD105-05, Research Triangle Park, NC, 27711, USA
| | - Timothy J Shafer
- Integrated Systems Toxicology Division, NHEERL, US EPA, MD105-05, Research Triangle Park, NC, 27711, USA.
| | - Jenna D Strickland
- Axion Biosystems, Atlanta, GA, USA
- Department of Pharmacology and Toxicology, Michigan State University, E. Lansing, MI, USA
| |
Collapse
|
38
|
Gottschling C, Dzyubenko E, Geissler M, Faissner A. The Indirect Neuron-astrocyte Coculture Assay: An In Vitro Set-up for the Detailed Investigation of Neuron-glia Interactions. J Vis Exp 2016. [PMID: 27911416 DOI: 10.3791/54757] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Proper neuronal development and function is the prerequisite of the developing and the adult brain. However, the mechanisms underlying the highly controlled formation and maintenance of complex neuronal networks are not completely understood thus far. The open questions concerning neurons in health and disease are diverse and reaching from understanding the basic development to investigating human related pathologies, e.g., Alzheimer's disease and Schizophrenia. The most detailed analysis of neurons can be performed in vitro. However, neurons are demanding cells and need the additional support of astrocytes for their long-term survival. This cellular heterogeneity is in conflict with the aim to dissect the analysis of neurons and astrocytes. We present here a cell-culture assay that allows for the long-term cocultivation of pure primary neurons and astrocytes, which share the same chemically defined medium, while being physically separated. In this setup, the cultures survive for up to four weeks and the assay is suitable for a diversity of investigations concerning neuron-glia interaction.
Collapse
Affiliation(s)
- Christine Gottschling
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University
| | - Egor Dzyubenko
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University
| | - Maren Geissler
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University;
| |
Collapse
|
39
|
Brown JP, Hall D, Frank CL, Wallace K, Mundy WR, Shafer TJ. Editor's Highlight: Evaluation of a Microelectrode Array-Based Assay for Neural Network Ontogeny Using Training Set Chemicals. Toxicol Sci 2016; 154:126-139. [PMID: 27492221 DOI: 10.1093/toxsci/kfw147] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Thousands of compounds in the environment have not been characterized for developmental neurotoxicity (DNT) hazard. To address this issue, methods to screen compounds rapidly for DNT hazard evaluation are necessary and are being developed for key neurodevelopmental processes. In order to develop an assay for network formation, this study evaluated effects of a training set of chemicals on network ontogeny by measuring spontaneous electrical activity in neural networks grown on microelectrode arrays (MEAs). Rat (0-24 h old) primary cortical cells were plated in 48 well-MEA plates and exposed to 6 compounds: acetaminophen, bisindolylmaleimide-1 (Bis-1), domoic acid, mevastatin, sodium orthovanadate, and loperamide for a period of 12 days. Spontaneous network activity was recorded on days 2, 5, 7, 9, and 12 and viability was assessed using the Cell Titer Blue assay on day 12. Network activity (e.g. mean firing rate [MFR], burst rate [BR], etc), increased between days 5 and 12. Random Forest analysis indicated that across all compounds and times, temporal correlation of firing patterns (r), MFR, BR, number of active electrodes and % of spikes in a burst were the most influential parameters in separating control from treated wells. All compounds except acetaminophen (≤ 30 µM) caused concentration-related effects on one or more of these parameters. Domoic acid and sodium orthovanadate altered several of these parameters in the absence of cytotoxicity. Although cytotoxicity was observed with Bis1, mevastatin, and loperamide, some parameters were affected by these compounds at concentrations below those resulting in cytotoxicity. These results demonstrate that this assay may be suitable for screening of compounds for DNT hazard identification.
Collapse
Affiliation(s)
| | - Diana Hall
- NHEERL, US EPA, Research Triangle Park, NC, USA
| | | | | | | | | |
Collapse
|
40
|
Aschner M, Ceccatelli S, Daneshian M, Fritsche E, Hasiwa N, Hartung T, Hogberg HT, Leist M, Li A, Mundi WR, Padilla S, Piersma AH, Bal-Price A, Seiler A, Westerink RH, Zimmer B, Lein PJ. Reference compounds for alternative test methods to indicate developmental neurotoxicity (DNT) potential of chemicals: example lists and criteria for their selection and use. ALTEX-ALTERNATIVES TO ANIMAL EXPERIMENTATION 2016; 34:49-74. [PMID: 27452664 PMCID: PMC5250586 DOI: 10.14573/altex.1604201] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/09/2016] [Indexed: 11/23/2022]
Abstract
There is a paucity of information concerning the developmental neurotoxicity (DNT) hazard posed by industrial and environmental chemicals. New testing approaches will most likely be based on batteries of alternative and complementary (non-animal) tests. As DNT is assumed to result from the modulation of fundamental neurodevelopmental processes (such as neuronal differentiation, precursor cell migration or neuronal network formation) by chemicals, the first generation of alternative DNT tests target these processes. The advantage of such types of assays is that they capture toxicants with multiple targets and modes-of-action. Moreover, the processes modelled by the assays can be linked to toxicity endophenotypes, i.e. alterations in neural connectivity that form the basis for neurofunctional deficits in man. The authors of this review convened in a workshop to define criteria for the selection of positive/negative controls, to prepare recommendations on their use, and to initiate the setup of a directory of reference chemicals. For initial technical optimization of tests, a set of >50 endpoint-specific control compounds was identified. For further test development, an additional “test” set of 33 chemicals considered to act directly as bona fide DNT toxicants is proposed, and each chemical is annotated to the extent it fulfills these criteria. A tabular compilation of the original literature used to select the test set chemicals provides information on statistical procedures, and toxic/non-toxic doses (both for pups and dams). Suggestions are provided on how to use the >100 compounds (including negative controls) compiled here to address specificity, adversity and use of alternative test systems.
Collapse
Affiliation(s)
| | | | - Mardas Daneshian
- Center for Alternatives to Animal Testing-Europe (CAAT-Europe), University of Konstanz, Germany
| | - Ellen Fritsche
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
| | - Nina Hasiwa
- Center for Alternatives to Animal Testing-Europe (CAAT-Europe), University of Konstanz, Germany
| | - Thomas Hartung
- Center for Alternatives to Animal Testing-Europe (CAAT-Europe), University of Konstanz, Germany.,Center for Alternatives to Animal Testing (CAAT), The Johns Hopkins University, Baltimore, MD, USA
| | - Helena T Hogberg
- Center for Alternatives to Animal Testing (CAAT), The Johns Hopkins University, Baltimore, MD, USA
| | - Marcel Leist
- Center for Alternatives to Animal Testing-Europe (CAAT-Europe), University of Konstanz, Germany.,In vitro Toxicology and Biomedicine, Dept inaugurated by the Doerenkamp-Zbinden Foundation at the University of Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology (KoRS-CB), Konstanz University
| | - Abby Li
- Exponent Inc.,San Francisco, USA
| | - William R Mundi
- United States Environmental Protection Agency (USEPA), NHEERL, Research Triangle Park, NC, USA
| | - Stephanie Padilla
- United States Environmental Protection Agency (USEPA), NHEERL, Research Triangle Park, NC, USA
| | - Aldert H Piersma
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.,Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Anna Bal-Price
- European Commission Joint Research Centre, Institute for Health and Consumer Protection, Ispra, Italy
| | - Andrea Seiler
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Remco H Westerink
- Neurotoxicology Research Group, Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, The Netherlands
| | | | - Pamela J Lein
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, USA.,Department of Molecular Biosciences, University of California, Davis, USA
| |
Collapse
|
41
|
Cotterill E, Hall D, Wallace K, Mundy WR, Eglen SJ, Shafer TJ. Characterization of Early Cortical Neural Network Development in Multiwell Microelectrode Array Plates. JOURNAL OF BIOMOLECULAR SCREENING 2016; 21:510-9. [PMID: 27028607 PMCID: PMC4904353 DOI: 10.1177/1087057116640520] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 11/16/2022]
Abstract
We examined neural network ontogeny using microelectrode array (MEA) recordings made in multiwell MEA (mwMEA) plates over the first 12 days in vitro (DIV). In primary cortical cultures, action potential spiking activity developed rapidly between DIV 5 and 12. Spiking was sporadic and unorganized at early DIV, and became progressively more organized with time, with bursting parameters, synchrony, and network bursting increasing between DIV 5 and 12. We selected 12 features to describe network activity; principal components analysis using these features demonstrated segregation of data by age at both the well and plate levels. Using random forest classifiers and support vector machines, we demonstrated that four features (coefficient of variation [CV] of within-burst interspike interval, CV of interburst interval, network spike rate, and burst rate) could predict the age of each well recording with >65% accuracy. When restricting the classification to a binary decision, accuracy improved to as high as 95%. Further, we present a novel resampling approach to determine the number of wells needed for comparing different treatments. Overall, these results demonstrate that network development on mwMEA plates is similar to development in single-well MEAs. The increased throughput of mwMEAs will facilitate screening drugs, chemicals, or disease states for effects on neurodevelopment.
Collapse
Affiliation(s)
- Ellese Cotterill
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
| | - Diana Hall
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Kathleen Wallace
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - William R Mundy
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Stephen J Eglen
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
| | - Timothy J Shafer
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| |
Collapse
|
42
|
Strickland JD, LeFew WR, Crooks J, Hall D, Ortenzio JN, Dreher K, Shafer TJ. In vitro screening of silver nanoparticles and ionic silver using neural networks yields differential effects on spontaneous activity and pharmacological responses. Toxicology 2016; 355-356:1-8. [DOI: 10.1016/j.tox.2016.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/26/2016] [Accepted: 05/10/2016] [Indexed: 12/21/2022]
|
43
|
Singh S, Srivastava A, Kumar V, Pandey A, Kumar D, Rajpurohit CS, Khanna VK, Yadav S, Pant AB. Stem Cells in Neurotoxicology/Developmental Neurotoxicology: Current Scenario and Future Prospects. Mol Neurobiol 2015; 53:6938-6949. [DOI: 10.1007/s12035-015-9615-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 12/03/2015] [Indexed: 12/26/2022]
|
44
|
Schultz L, Zurich MG, Culot M, da Costa A, Landry C, Bellwon P, Kristl T, Hörmann K, Ruzek S, Aiche S, Reinert K, Bielow C, Gosselet F, Cecchelli R, Huber CG, Schroeder OHU, Gramowski-Voss A, Weiss DG, Bal-Price A. Evaluation of drug-induced neurotoxicity based on metabolomics, proteomics and electrical activity measurements in complementary CNS in vitro models. Toxicol In Vitro 2015; 30:138-65. [DOI: 10.1016/j.tiv.2015.05.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 03/26/2015] [Accepted: 05/18/2015] [Indexed: 12/14/2022]
|
45
|
Strickland JD, Lefew WR, Crooks J, Hall D, Ortenzio JNR, Dreher K, Shafer TJ. In vitroscreening of metal oxide nanoparticles for effects on neural function using cortical networks on microelectrode arrays. Nanotoxicology 2015; 10:619-28. [DOI: 10.3109/17435390.2015.1107142] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
46
|
In VitroDevelopmental Neurotoxicity Following Chronic Exposure to 50 Hz Extremely Low-Frequency Electromagnetic Fields in Primary Rat Cortical Cultures. Toxicol Sci 2015; 149:433-40. [DOI: 10.1093/toxsci/kfv242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
47
|
Regalia G, Biffi E, Achilli S, Ferrigno G, Menegon A, Pedrocchi A. Development of a bench-top device for parallel climate-controlled recordings of neuronal cultures activity with microelectrode arrays. Biotechnol Bioeng 2015; 113:403-13. [DOI: 10.1002/bit.25811] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 08/06/2015] [Accepted: 08/18/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Giulia Regalia
- Neuroengineering and Medical Robotics Laboratory; Electronics, Information and Bioengineering Department; Politecnico di Milano; 20133 Milan Italy
| | - Emilia Biffi
- Neuroengineering and Medical Robotics Laboratory; Electronics, Information and Bioengineering Department; Politecnico di Milano; 20133 Milan Italy
| | - Silvia Achilli
- Neuroengineering and Medical Robotics Laboratory; Electronics, Information and Bioengineering Department; Politecnico di Milano; 20133 Milan Italy
| | - Giancarlo Ferrigno
- Neuroengineering and Medical Robotics Laboratory; Electronics, Information and Bioengineering Department; Politecnico di Milano; 20133 Milan Italy
| | - Andrea Menegon
- Advanced Light and Electron Microscopy Bio-Imaging Centre; Experimental Imaging Centre; San Raffaele Scientific Institute; 20132 Milan Italy
| | - Alessandra Pedrocchi
- Neuroengineering and Medical Robotics Laboratory; Electronics, Information and Bioengineering Department; Politecnico di Milano; 20133 Milan Italy
| |
Collapse
|
48
|
Citrate-stabilized gold nanoparticles as negative controls for measurements of neurite outgrowth. Toxicol In Vitro 2015; 29:187-94. [PMID: 25458488 DOI: 10.1016/j.tiv.2014.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 11/21/2022]
Abstract
Gold nanoparticles (AuNPs) are promising candidates for medical diagnostics and therapeutics, due to their chemical stability, optical properties, and ease of functionalization. Citrate-stabilized reference materials also have potential as negative controls in toxicology studies of other nanoparticles. Here we examine the impact of 30 nm particles on the in vitro development of rat-cortex neural progenitor cells (NPCs), which mimic aspects of the developing neurological environment. AuNPs dispersed in a low serum culture medium initially agglomerated, but then remained stable during a three day incubation period, and agglomerated only slightly during a ten day incubation period, as determined by dynamic light scattering. Transmission electron microscopy indicated the presence of individual nanoparticles at all time points examined. Fixed cells were cross-sectioned by ion milling and imaged by scanning electronmicroscopy and helium-ion microscopy to evaluate particle incorporation. Individual nanoparticles could be resolved inside cross-sectioned cells. AuNPs were incubated with developing NPCs for ten days at concentrations of 0.5 μg/mL Au, 0.1 μg/mL Au, or 0.05 μg/mL Au. Adenosine triphosphate levels, as determined by bioluminescence measurements sensitive to low cell numbers, were not affected by AuNPs and the particles did not interfere with the assay. Multiple endpoints of neurite outgrowth were not altered by AuNPs, in particular, total neurite outgrowth per cell, a sensitive measure of neuronal development. Slide-level comparisons demonstrated the consistent response of NPCs to gold nanoparticles and a positive control chemical, neuroactive lithium. These results indicate that 30 nm citrate-stabilized AuNPs could serve as negative-control reference materials for in vitro measurements of neurite outgrowth.
Collapse
|
49
|
Wallace K, Strickland JD, Valdivia P, Mundy WR, Shafer TJ. A multiplexed assay for determination of neurotoxicant effects on spontaneous network activity and viability from microelectrode arrays. Neurotoxicology 2015; 49:79-85. [DOI: 10.1016/j.neuro.2015.05.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 05/21/2015] [Accepted: 05/21/2015] [Indexed: 12/18/2022]
|
50
|
Harrill JA, Chen H, Streifel KM, Yang D, Mundy WR, Lein PJ. Ontogeny of biochemical, morphological and functional parameters of synaptogenesis in primary cultures of rat hippocampal and cortical neurons. Mol Brain 2015; 8:10. [PMID: 25757474 PMCID: PMC4339650 DOI: 10.1186/s13041-015-0099-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 01/30/2015] [Indexed: 11/23/2022] Open
Abstract
Background Synaptogenesis is a critical neurodevelopmental process whereby pre- and postsynaptic neurons form apposed sites of contact specialized for chemical neurotransmission. Many neurodevelopmental disorders are thought to reflect altered patterns of synaptic connectivity, including imbalances between excitatory and inhibitory synapses. Developing rapid throughput approaches for assessing synaptogenesis will facilitate toxicologic and drug screening studies of neurodevelopmental disorders. The current study describes the use of high-content imaging to quantify the ontogeny of excitatory and inhibitory synapses using in vitro models of neurodevelopment. These data are compared to biochemical and functional measures of synaptogenesis. Results The ontogenetic patterns of synapse formation were compared between primary rodent hippocampal and cortical neurons over 28 days in vitro (DIV). As determined by ELISA, the increase in synaptophysin expression levels as cultures matured was similar between hippocampal and cortical cultures. High-content imaging of immunoreactivity of excitatory and inhibitory synaptic biomarkers demonstrated an overall greater number of synapses in hippocampal relative to cortical neurons with marked differences in the pattern of inhibitory synapse development between these two neuronal cell types. Functional assays revealed that both the mean firing rates and mean bursting rates were significantly increased in cortical cultures relative to hippocampal cultures. This difference may reflect decreased inhibitory synaptic tone in cortical versus hippocampal cultures. Conclusions These data demonstrate differences and similarities in the ontogeny of synaptogenesis between hippocampal and cortical neurons, depending on the biological level examined. Assessment of synaptophysin protein levels by ELISA showed a general increase in synapse formation in both cell types with increasing time in culture, while high-content imaging was able to delineate cell type-dependent differences in formation of excitatory versus inhibitory synapses. The functional significance of differences in the balance of excitatory to inhibitory synapses was confirmed by the assessment of network activity using microelectrode arrays. These results suggest that high-content imaging and microelectrode arrays provide complementary approaches for quantitative assessment of synaptogenesis, which should provide a robust readout of toxicologic and pharmacologic effects on this critical neurodevelopmental event.
Collapse
|