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Terrasso AP, Silva AC, Filipe A, Pedroso P, Ferreira AL, Alves PM, Brito C. Human neuron-astrocyte 3D co-culture-based assay for evaluation of neuroprotective compounds. J Pharmacol Toxicol Methods 2017; 83:72-79. [DOI: 10.1016/j.vascn.2016.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/27/2016] [Accepted: 10/09/2016] [Indexed: 11/25/2022]
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Hill E, Nagel D, Parri R, Coleman M. Stem cell-derived astrocytes: are they physiologically credible? J Physiol 2016; 594:6595-6606. [PMID: 26634807 PMCID: PMC5108894 DOI: 10.1113/jp270658] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/28/2015] [Indexed: 01/29/2023] Open
Abstract
Astrocytes are now increasingly acknowledged as having fundamental and sophisticated roles in brain function and dysfunction. Unravelling the complex mechanisms that underlie human brain astrocyte-neuron interactions is therefore an essential step on the way to understanding how the brain operates. Insights into astrocyte function to date have almost exclusively been derived from studies conducted using murine or rodent models. Whilst these have led to significant discoveries, preliminary work with human astrocytes has revealed a hitherto unknown range of astrocyte types with potentially greater functional complexity and increased neuronal interaction with respect to animal astrocytes. It is becoming apparent, therefore, that many important functions of astrocytes will only be discovered by direct physiological interrogation of human astrocytes. Recent advancements in the field of stem cell biology have provided a source of human-based models. These will provide a platform to facilitate our understanding of normal astrocyte functions as well as their role in CNS pathology. A number of recent studies have demonstrated that stem cell-derived astrocytes exhibit a range of properties, suggesting that they may be functionally equivalent to their in vivo counterparts. Further validation against in vivo models will ultimately confirm the future utility of these stem cell-based approaches in fulfilling the need for human-based cellular models for basic and clinical research. In this review we discuss the roles of astrocytes in the brain and highlight the extent to which human stem cell-derived astrocytes have demonstrated functional activities that are equivalent to those observed in vivo.
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Affiliation(s)
- Eric Hill
- Aston Research Centre for Healthy AgeingLife and Health SciencesAston UniversityBirminghamB4 7ETUK
| | - David Nagel
- Aston Research Centre for Healthy AgeingLife and Health SciencesAston UniversityBirminghamB4 7ETUK
| | - Rheinallt Parri
- Aston Research Centre for Healthy AgeingLife and Health SciencesAston UniversityBirminghamB4 7ETUK
| | - Michael Coleman
- Aston Research Centre for Healthy AgeingLife and Health SciencesAston UniversityBirminghamB4 7ETUK
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Functional metabolic interactions of human neuron-astrocyte 3D in vitro networks. Sci Rep 2016; 6:33285. [PMID: 27619889 PMCID: PMC5020407 DOI: 10.1038/srep33285] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 08/19/2016] [Indexed: 01/27/2023] Open
Abstract
The generation of human neural tissue-like 3D structures holds great promise for disease modeling, drug discovery and regenerative medicine strategies. Promoting the establishment of complex cell-cell interactions, 3D culture systems enable the development of human cell-based models with increased physiological relevance, over monolayer cultures. Here, we demonstrate the establishment of neuronal and astrocytic metabolic signatures and shuttles in a human 3D neural cell model, namely the glutamine-glutamate-GABA shuttle. This was indicated by labeling of neuronal GABA following incubation with the glia-specific substrate [2-(13)C]acetate, which decreased by methionine sulfoximine-induced inhibition of the glial enzyme glutamine synthetase. Cell metabolic specialization was further demonstrated by higher pyruvate carboxylase-derived labeling in glutamine than in glutamate, indicating its activity in astrocytes and not in neurons. Exposure to the neurotoxin acrylamide resulted in intracellular accumulation of glutamate and decreased GABA synthesis. These results suggest an acrylamide-induced impairment of neuronal synaptic vesicle trafficking and imbalanced glutamine-glutamate-GABA cycle, due to loss of cell-cell contacts at synaptic sites. This work demonstrates, for the first time to our knowledge, that neural differentiation of human cells in a 3D setting recapitulates neuronal-astrocytic metabolic interactions, highlighting the relevance of these models for toxicology and better understanding the crosstalk between human neural cells.
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Sanders AW, Jeerage KM, Schwartz CL, Curtin AE, Chiaramonti AN. Gold Nanoparticle Quantitation by Whole Cell Tomography. ACS NANO 2015; 9:11792-9. [PMID: 26563983 DOI: 10.1021/acsnano.5b03815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Many proposed biomedical applications for engineered gold nanoparticles require their incorporation by mammalian cells in specific numbers and locations. Here, the number of gold nanoparticles inside of individual mammalian stem cells was characterized using fast focused ion beam-scanning electron microscopy based tomography. Enhanced optical microscopy was used to provide a multiscale map of the in vitro sample, which allows cells of interest to be identified within their local environment. Cells were then serially sectioned using a gallium ion beam and imaged using a scanning electron beam. To confirm the accuracy of single cross sections, nanoparticles in similar cross sections were imaged using transmission electron microscopy and scanning helium ion microscopy. Complete tomographic series were then used to count the nanoparticles inside of each cell and measure their spatial distribution. We investigated the influence of slice thickness on counting single particles and clusters as well as nanoparticle packing within clusters. For 60 nm citrate stabilized particles, the nanoparticle cluster packing volume is 2.15 ± 0.20 times the volume of the bare gold nanoparticles.
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Affiliation(s)
- Aric W Sanders
- Quantum Electronics and Photonics Division, National Institute of Standards and Technology (NIST) , Boulder, Colorado 59840, United States
| | - Kavita M Jeerage
- Applied Chemicals and Materials Division, National Institute of Standards and Technology (NIST) , Boulder, Colorado 59840, United States
| | - Cindi L Schwartz
- Department of Molecular, Cell, and Developmental Biology, University of Colorado , Boulder, Colorado 59840, United States
| | - Alexandra E Curtin
- Quantum Electronics and Photonics Division, National Institute of Standards and Technology (NIST) , Boulder, Colorado 59840, United States
- Applied Chemicals and Materials Division, National Institute of Standards and Technology (NIST) , Boulder, Colorado 59840, United States
| | - Ann N Chiaramonti
- Applied Chemicals and Materials Division, National Institute of Standards and Technology (NIST) , Boulder, Colorado 59840, United States
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Woehrling EK, Parri HR, Tse EHY, Hill EJ, Maidment ID, Fox GC, Coleman MD. A predictive in vitro model of the impact of drugs with anticholinergic properties on human neuronal and astrocytic systems. PLoS One 2015; 10:e0118786. [PMID: 25738989 PMCID: PMC4349811 DOI: 10.1371/journal.pone.0118786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/22/2015] [Indexed: 11/19/2022] Open
Abstract
The link between off-target anticholinergic effects of medications and acute cognitive impairment in older adults requires urgent investigation. We aimed to determine whether a relevant in vitro model may aid the identification of anticholinergic responses to drugs and the prediction of anticholinergic risk during polypharmacy. In this preliminary study we employed a co-culture of human-derived neurons and astrocytes (NT2.N/A) derived from the NT2 cell line. NT2.N/A cells possess much of the functionality of mature neurons and astrocytes, key cholinergic phenotypic markers and muscarinic acetylcholine receptors (mAChRs). The cholinergic response of NT2 astrocytes to the mAChR agonist oxotremorine was examined using the fluorescent dye fluo-4 to quantitate increases in intracellular calcium [Ca2+]i. Inhibition of this response by drugs classified as severe (dicycloverine, amitriptyline), moderate (cyclobenzaprine) and possible (cimetidine) on the Anticholinergic Cognitive Burden (ACB) scale, was examined after exposure to individual and pairs of compounds. Individually, dicycloverine had the most significant effect regarding inhibition of the astrocytic cholinergic response to oxotremorine, followed by amitriptyline then cyclobenzaprine and cimetidine, in agreement with the ACB scale. In combination, dicycloverine with cyclobenzaprine had the most significant effect, followed by dicycloverine with amitriptyline. The order of potency of the drugs in combination frequently disagreed with predicted ACB scores derived from summation of the individual drug scores, suggesting current scales may underestimate the effect of polypharmacy. Overall, this NT2.N/A model may be appropriate for further investigation of adverse anticholinergic effects of multiple medications, in order to inform clinical choices of suitable drug use in the elderly.
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Affiliation(s)
- Elizabeth K. Woehrling
- School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
| | - H. Rheinallt Parri
- School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
| | - Erin H. Y. Tse
- School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
| | - Eric J. Hill
- Aston Research Centre into Healthy Ageing (ARCHA), Aston University, Birmingham, B4 7ET, United Kingdom
| | - Ian D. Maidment
- Aston Research Centre into Healthy Ageing (ARCHA), Aston University, Birmingham, B4 7ET, United Kingdom
| | - G. Christopher Fox
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Michael D. Coleman
- School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, United Kingdom
- * E-mail:
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Woehrling EK, Hill EJ, Nagel D, Coleman MD. Brain-derived neurotrophic factor as an indicator of chemical neurotoxicity: an animal-free CNS cell culture model. Altern Lab Anim 2014; 41:503-11. [PMID: 24512234 DOI: 10.1177/026119291304100613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Recent changes to the legislation on chemicals and cosmetics testing call for a change in the paradigm regarding the current 'whole animal' approach for identifying chemical hazards, including the assessment of potential neurotoxins. Accordingly, since 2004, we have worked on the development of the integrated co-culture of post-mitotic, human-derived neurons and astrocytes (NT2.N/A), for use as an in vitro functional central nervous system (CNS) model. We have used it successfully to investigate indicators of neurotoxicity. For this purpose, we used NT2.N/A cells to examine the effects of acute exposure to a range of test chemicals on the cellular release of brain-derived neurotrophic factor (BDNF). It was demonstrated that the release of this protective neurotrophin into the culture medium (above that of control levels) occurred consistently in response to sub-cytotoxic levels of known neurotoxic, but not non-neurotoxic, chemicals. These increases in BDNF release were quantifiable, statistically significant, and occurred at concentrations below those at which cell death was measureable, which potentially indicates specific neurotoxicity, as opposed to general cytotoxicity. The fact that the BDNF immunoassay is non-invasive, and that NT2.N/A cells retain their functionality for a period of months, may make this system useful for repeated-dose toxicity testing, which is of particular relevance to cosmetics testing without the use of laboratory animals. In addition, the production of NT2.N/A cells without the use of animal products, such as fetal bovine serum, is being explored, to produce a fully-humanised cellular model.
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Affiliation(s)
- Elizabeth K Woehrling
- Mechanisms of Toxicity Group, School of Life and Health Sciences, Aston University, Birmingham, UK
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Functional astrocyte-neuron lactate shuttle in a human stem cell-derived neuronal network. J Cereb Blood Flow Metab 2013; 33:1386-93. [PMID: 23715062 PMCID: PMC3764384 DOI: 10.1038/jcbfm.2013.81] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/28/2013] [Accepted: 04/27/2013] [Indexed: 12/23/2022]
Abstract
The NT2.D1 cell line is one of the most well-documented embryocarcinoma cell lines, and can be differentiated into neurons and astrocytes. Great focus has also been placed on defining the electrophysiological properties of the neuronal cells, and more recently we have investigated the functional properties of their associated astrocytes. We now show for the first time that human stem cell-derived astrocytes produce glycogen and that co-cultures of these cells demonstrate a functional astrocyte-neuron lactate shuttle (ANLS). The ANLS hypothesis proposes that during neuronal activity, glutamate released into the synaptic cleft is taken up by astrocytes and triggers glucose uptake, which is converted into lactate and released via monocarboxylate transporters for neuronal use. Using mixed cultures of NT2-derived neurons and astrocytes, we have shown that these cells modulate their glucose uptake in response to glutamate. Additionally, we demonstrate that in response to increased neuronal activity and under hypoglycaemic conditions, co-cultures modulate glycogen turnover and increase lactate production. Similar results were also shown after treatment with glutamate, potassium, isoproterenol, and dbcAMP. Together, these results demonstrate for the first time a functional ANLS in a human stem cell-derived co-culture.
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Neurite outgrowth and differentiation of rat cortex progenitor cells are sensitive to lithium chloride at non-cytotoxic exposures. Neurotoxicology 2012; 33:1170-9. [PMID: 22771960 DOI: 10.1016/j.neuro.2012.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 06/20/2012] [Accepted: 06/25/2012] [Indexed: 01/17/2023]
Abstract
Neuron-specific in vitro screening strategies have the potential to accelerate the evaluation of chemicals for neurotoxicity. We examined neurite outgrowth as a measure of neuronal response with a commercially available rat cortex progenitor cell model, where cells were exposed to a chemical during a period of cell differentiation. In control cultures, the fraction of beta-III-tubulin positive neurons and their neurite length increased significantly with time, indicating differentiation of the progenitor cells. Expression of glial fibrillary acidic protein, an astrocyte marker, also increased significantly with time. By seeding progenitor cells at varying densities, we demonstrated that neurite length was influenced by cell-cell spacing. After ten days, cultures seeded at densities of 1000 cells/mm(2) or lower had significantly shorter neurites than cultures seeded at densities of 1250 cells/mm(2) or higher. Progenitor cells were exposed to lithium, a neuroactive chemical with diverse modes of action. Cultures exposed to 30 mmol/L or 10 mmol/L lithium chloride (LiCl) had significantly lower metabolic activity than control cultures, as reported by adenosine triphosphate content, and no neurons were observed after ten days of exposure. Cultures exposed to 3 mmol/L, 1 mmol/L, or 0.3 mmol/L LiCl, which encompass lithium's therapeutic range, had metabolic activity similar to control cultures. These cultures exhibited concentration-dependent decreases in neurite outgrowth after ten days of LiCl exposure. Neurite outgrowth results were relatively robust, regardless of the evaluation methodology. This work demonstrates that measurement of neurite outgrowth in differentiating progenitor cell cultures can be a sensitive endpoint for neuronal response under non-cytotoxic exposure conditions.
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Hill EJ, Jiménez-González C, Tarczyluk M, Nagel DA, Coleman MD, Parri HR. NT2 derived neuronal and astrocytic network signalling. PLoS One 2012; 7:e36098. [PMID: 22567128 PMCID: PMC3342170 DOI: 10.1371/journal.pone.0036098] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 03/30/2012] [Indexed: 12/16/2022] Open
Abstract
A major focus of stem cell research is the generation of neurons that may then be implanted to treat neurodegenerative diseases. However, a picture is emerging where astrocytes are partners to neurons in sustaining and modulating brain function. We therefore investigated the functional properties of NT2 derived astrocytes and neurons using electrophysiological and calcium imaging approaches. NT2 neurons (NT2Ns) expressed sodium dependent action potentials, as well as responses to depolarisation and the neurotransmitter glutamate. NT2Ns exhibited spontaneous and coordinated calcium elevations in clusters and in extended processes, indicating local and long distance signalling. Tetrodotoxin sensitive network activity could also be evoked by electrical stimulation. Similarly, NT2 astrocytes (NT2As) exhibited morphology and functional properties consistent with this glial cell type. NT2As responded to neuronal activity and to exogenously applied neurotransmitters with calcium elevations, and in contrast to neurons, also exhibited spontaneous rhythmic calcium oscillations. NT2As also generated propagating calcium waves that were gap junction and purinergic signalling dependent. Our results show that NT2 derived astrocytes exhibit appropriate functionality and that NT2N networks interact with NT2A networks in co-culture. These findings underline the utility of such cultures to investigate human brain cell type signalling under controlled conditions. Furthermore, since stem cell derived neuron function and survival is of great importance therapeutically, our findings suggest that the presence of complementary astrocytes may be valuable in supporting stem cell derived neuronal networks. Indeed, this also supports the intriguing possibility of selective therapeutic replacement of astrocytes in diseases where these cells are either lost or lose functionality.
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Affiliation(s)
- Eric J. Hill
- Aston Research Centre into Healthy Ageing (ARCHA), Aston University, Birmingham, West Midlands, United Kingdom
| | | | - Marta Tarczyluk
- Aston Research Centre into Healthy Ageing (ARCHA), Aston University, Birmingham, West Midlands, United Kingdom
| | - David A. Nagel
- School of Life and Health Sciences, Aston University, Birmingham, West Midlands, United Kingdom
| | - Michael D. Coleman
- School of Life and Health Sciences, Aston University, Birmingham, West Midlands, United Kingdom
| | - H. Rheinallt Parri
- School of Life and Health Sciences, Aston University, Birmingham, West Midlands, United Kingdom
- * E-mail:
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Woehrling EK, Hill EJ, Torr EE, Coleman MD. Single-cell ELISA and flow cytometry as methods for highlighting potential neuronal and astrocytic toxicant specificity. Neurotox Res 2010; 19:472-83. [PMID: 20552314 DOI: 10.1007/s12640-010-9202-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 05/09/2010] [Accepted: 06/02/2010] [Indexed: 12/11/2022]
Abstract
The timeline imposed by recent worldwide chemical legislation is not amenable to conventional in vivo toxicity testing, requiring the development of rapid, economical in vitro screening strategies which have acceptable predictive capacities. When acquiring regulatory neurotoxicity data, distinction on whether a toxic agent affects neurons and/or astrocytes is essential. This study evaluated neurofilament (NF) and glial fibrillary acidic protein (GFAP) directed single-cell (S-C) ELISA and flow cytometry as methods for distinguishing cell-specific cytoskeletal responses, using the established human NT2 neuronal/astrocytic (NT2.N/A) co-culture model and a range of neurotoxic (acrylamide, atropine, caffeine, chloroquine, nicotine) and non-neurotoxic (chloramphenicol, rifampicin, verapamil) test chemicals. NF and GFAP directed flow cytometry was able to identify several of the test chemicals as being specifically neurotoxic (chloroquine, nicotine) or astrocytoxic (atropine, chloramphenicol) via quantification of cell death in the NT2.N/A model at cytotoxic concentrations using the resazurin cytotoxicity assay. Those neurotoxicants with low associated cytotoxicity are the most significant in terms of potential hazard to the human nervous system. The NF and GFAP directed S-C ELISA data predominantly demonstrated the known neurotoxicants only to affect the neuronal and/or astrocytic cytoskeleton in the NT2.N/A cell model at concentrations below those affecting cell viability. This report concluded that NF and GFAP directed S-C ELISA and flow cytometric methods may prove to be valuable additions to an in vitro screening strategy for differentiating cytotoxicity from specific neuronal and/or astrocytic toxicity. Further work using the NT2.N/A model and a broader array of toxicants is appropriate in order to confirm the applicability of these methods.
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Affiliation(s)
- E K Woehrling
- School of Life and Health Sciences, Aston University, Aston Street, Birmingham, UK.
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Dahm L, Klugmann F, Gonzalez-Algaba A, Reuss B. Tamoxifen and raloxifene modulate gap junction coupling during early phases of retinoic acid-dependent neuronal differentiation of NTera2/D1 cells. Cell Biol Toxicol 2010; 26:579-91. [PMID: 20437090 PMCID: PMC2959160 DOI: 10.1007/s10565-010-9165-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 04/12/2010] [Indexed: 01/21/2023]
Abstract
Gap junctions (GJ) represent a cellular communication system known to influence neuronal differentiation and survival. To assess a putative role of this system for neural effects of tamoxifen (TAM) and raloxifene (RAL), we used the human teratocarcinoma cell line NTera2/D1, retinoic acid (RA)-dependent neuronal differentiation of which is regulated by gap junctions formed of connexin43 (Cx43). As demonstrated by Western blot analysis, concentrations above 1 µmol/l for TAM, and 0.1 µmol/l for RAL lead to a temporary time- and concentration-dependent increase in Cx43 immunoreactivity, which reached a peak for TAM after 1 day and for RAL after 2 days. Immunocytochemical stainings revealed the increase in Cx43 immunoreactivity to result from an accumulation in intracellular compartments such as the Golgi apparatus or lysosomes. In addition, TAM and RAL were able to prevent the RA-dependent decrease of Cx43 immunoreactivity in NTera2/D1 cells, normally observed during neuronal differentiation. This suggested a suppression of neuronal differentiation to result from these substances. According to this, treatment of NTera2/D1 cells with 10 µmol/l TAM or RAL during weeks 1 and 2 of a 6 weeks RA-driven differentiation schedule impaired, whereas treatment during weeks 5 and 6 did not impair, neuronal differentiation of these cells. Modulation of GJ coupling between NTera2/D1 cells by TAM and RAL seems therefore to perturb early neuronal differentiation, whereas differentiated neurons in the mature brain seem to be not affected. These effects could be of importance for actions of TAM and RAL on early embryonic steps of nervous system formation.
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Affiliation(s)
- Liane Dahm
- Center for Anatomy-Neuroanatomy, University of Göttingen, Kreuzbergring 36, 37075, Göttingen, Germany
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