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| 2. |
- Forsby, A, et al.
(author)
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Neuronal in vitro models for the estimation of acute systemic toxicity.
- 2009
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In: Toxicology in vitro : an international journal published in association with BIBRA. - : Elsevier BV. - 1879-3177. ; 23:8, s. 1564-1569
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Journal article (peer-reviewed)abstract
- The objective of the EU funded integrated project "ACuteTox" is to develop a strategy in which general cytotoxicity, together with organ-specific endpoints and biokinetic features, are taken into consideration in the in vitro prediction of oral acute systemic toxicity. With regard to the nervous system, the effects of 23 reference chemicals were tested with approximately 50 endpoints, using a neuronal cell line, primary neuronal cell cultures, brain slices and aggregated brain cell cultures. Comparison of the in vitro neurotoxicity data with general cytotoxicity data generated in a non-neuronal cell line and with in vivo data such as acute human lethal blood concentration, revealed that GABA(A) receptor function, acetylcholine esterase activity, cell membrane potential, glucose uptake, total RNA expression and altered gene expression of NF-H, GFAP, MBP, HSP32 and caspase-3 were the best endpoints to use for further testing with 36 additional chemicals. The results of the second analysis showed that no single neuronal endpoint could give a perfect improvement in the in vitro-in vivo correlation, indicating that several specific endpoints need to be analysed and combined with biokinetic data to obtain the best correlation with in vivo acute toxicity.
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| 3. |
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| 4. |
- DeJongh, J, et al.
(author)
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Estimation of systemic toxicity of acrylamide by integration of in vitro toxicity data with kinetic simulations.
- 1999
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In: Toxicology and Applied Pharmacology. - : Elsevier BV. - 0041-008X .- 1096-0333. ; 158:3, s. 261-268
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Journal article (peer-reviewed)abstract
- Neurodegenerative properties of acrylamide were studied in vitro by exposure of differentiated SH-SY5Y human neuroblastoma cells for 72 h. The number of neurites per cell and the total cellular protein content were determined every 24 h throughout the exposure and the subsequent 96-h recovery period. Using kinetic data on the metabolism of acrylamide in rat, a biokinetic model was constructed in which the in vitro toxicity data were integrated. Using this model, we estimated the acute and subchronic toxicity of acrylamide for the rat in vivo. These estimations were compared to experimentally derived lowest observed effect doses (LOEDs) for daily intraperitoneal exposure (1, 10, 30, and 90 days) to acrylamide. The estimated LOEDs differed maximally twofold from the experimental LOEDs, and the nonlinear response to acrylamide exposure over time was simulated correctly. It is concluded that the integration of the present in vitro toxicity data with kinetic data gives adequate estimates of acute and subchronic neurotoxicity resulting from acrylamide exposure.
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| 5. |
- Hinojosa, Maria G., et al.
(author)
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Effects of cylindrospermopsin, chlorpyrifos and their combination in a SH-SY5Y cell model concerning developmental neurotoxicity
- 2024
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In: Ecotoxicology and Environmental Safety. - 0147-6513 .- 1090-2414. ; 269
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Journal article (peer-reviewed)abstract
- The cyanotoxin cylindrospermopsin (CYN) has been postulated to cause neurotoxicity, although the studies in this concern are very few. In addition, some studies in vitro indicate its possible effects on development. Furthermore, pesticides can be present in the same environmental samples as cyanotoxins. Therefore, chlor-pyrifos (CPF) has been one of the most common pesticides used worldwide. The aim of this report was to study the effects of CYN, isolated and in combination with CPF, in a developmental neurotoxicity in vitro model. The human neuroblastoma SH-SY5Y cell line was exposed during 6 days of differentiation to both toxics to study their effects on cell viability and neurite outgrowth. To further evaluate effects of both toxicants on cholinergic signaling, their agonistic and antagonistic activities on the alpha 7 homomeric nicotinic acetylcholine receptor (nAChR) were studied upon acute exposure. Moreover, a transcriptomic analysis by qPCR was performed after 6 days of CYN-exposure during differentiation. The results showed a concentration-dependent decrease on both cell viability and neurite outgrowth for both toxics isolated, leading to effective concentration 20 (EC20) values of 0.35 mu M and 0.097 mu M for CYN on cell viability and neurite outgrowth, respectively, and 100 mu M and 58 mu M for CPF, while the combination demonstrated no significant variations. In addition, 95 mu M and 285 mu M CPF demonstrated to act as an antagonist to nicotine on the nAChR, although CYN up to 2.4 mu M had no effect on the efficacy of these receptors. Additionally, the EC20 for CYN (0.097 mu M) on neurite outgrowth downregulated expression of the 5 genes NTNG2 (netrin G2), KCNJ11 (potassium channel), SLC18A3 (vesicular acetylcholine transporter), APOE (apolipoprotein E), and SEMA6B (semaphorin 6B), that are all important for neuronal development. Thus, this study points out the importance of studying the effects of CYN in terms of neurotoxicity and developmental neurotoxicity.
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| 6. |
- Andres, M I, et al.
(author)
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Polygodial-induced noradrenaline release in human neuroblastoma SH-SY5Y cells.
- 1997
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In: Toxicology in Vitro. - 0887-2333 .- 1879-3177. ; 11:5, s. 509-11
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Journal article (peer-reviewed)abstract
- Polygodial is a natural sesquiterpene which exhibits pronounced pungency and a powerful antifeedant activity. At low concentrations, which do not alter general cell membrane permeability, polygodial increases the intracellular concentration of free calcium ([Ca(2+)](i)). Sensory neurotransmission depends on noradrenaline (NA) release, and vesicular exocytosis, in turn, is dependent on an increase in [Ca(2+)](i). The nociceptive response induced by polygodial could therefore be directly linked to intracellular calcium levels. Consequently, the objective of this work was to investigate the effect of polygodial on NA release. The human neuroblastoma cell line SH-SY5Y was selected as an in vitro model for sensory neurones. Semiconfluent cells were preloaded with tritiated NA ([(3)H]NA). After 3 min exposure of polygodial to the cells, released and unreleased radioactivity were measured. Polygodial induced a significant [(3)H]NA release at concentrations between 0.1 and 0.5 mug/ml with a maximum effect at 0.2 mug/ml (40% increased release of [(3)H]NA as compared with unstimulated control cells). No polygodial-induced transmitter release was seen at 3.5 and 5 mug/ml. For comparison, carbachol (1 rim) increased [(3)H]NA release by 10% and the KCl-induced (100 mm) [(3)H]NA release increased by 8% as compared with unstimulated SH-SY5Y cells. In conclusion polygodial, at the concentrations 0.1-0.5 mug/ml (equal to 0.4-2 mum), induces NA release which is dependent on polygodial-induced increase in [Ca(2+)](i).
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| 7. |
- Axelsson, V, et al.
(author)
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Glutathione intensifies gliotoxin-induced cytotoxicity in human neuroblastoma SH-SY5Y cells.
- 2006
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In: Cell Biology and Toxicology. - : Springer Science and Business Media LLC. - 0742-2091 .- 1573-6822. ; 22:2, s. 127-36
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Journal article (peer-reviewed)abstract
- Gliotoxin is a fungal second metabolite produced by diverse species that can be found in compost, stored crops, moist animal feed and sawdust. The role of glutathione in gliotoxin-induced toxicity was studied in order to elucidate the toxic mechanisms leading to neurite degeneration and cell death in differentiated human neuroblastoma (SH-SY5Y) cells. After 72 h of exposure to gliotoxin, moderate cytotoxicity was induced at 0.1 micromol/L, which was more severe at higher concentrations. A reduction in the number of neurites per cell was also observed. By decreasing the level of intracellular glutathione with L: -buthionine-sulfoxamine (BSO) a specific inhibitor of glutathione synthesis, the cytotoxic effect of gliotoxin was significantly attenuated. The gliotoxin-induced cytotoxicity was also slightly reduced by the antioxidant vitamin C. However, the neurite degenerative effect was not altered by BSO, or by vitamin C. A concentration-dependent increase in the ratio between oxidized and reduced forms of glutathione, as well as the total intracellular glutathione levels, was noted after exposure to gliotoxin. The increase of glutathione was also reflected in western blot analyses showing a tendency for the regulatory subunit of gamma-glutamylcysteine synthetase to be upregulated. In addition, the activity of glutathione reductase was slightly increased in gliotoxin-exposed cells. These results indicate that glutathione promotes gliotoxin-induced cytotoxicity, probably by reducing the ETP (epipolythiodioxopiperazine) disulfide bridge to the dithiol form.
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| 8. |
- Dejongh, J, et al.
(author)
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An Integrated Approach to the Prediction of Systemic Toxicity using Computer-based Biokinetic Models and Biological In vitro Test Methods : Overview of a Prevalidation Study Based on the ECITTS Project.
- 1999
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In: Toxicology in Vitro. - 0887-2333 .- 1879-3177. ; 13:4-5, s. 549-54
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Journal article (peer-reviewed)abstract
- Chemical toxicity was estimated by integrating in vitro study results with physiologically-based biokinetic models for eight neurotoxic compounds (benzene, toluene, lindane, acrylamide, parathion/oxon, caffeine, diazepam and phenytoin). In vitro studies on general and specific neurotoxicity were performed and biotransformation and tissue-blood distribution studies were used in modelling the biokinetic behaviour of the compounds. Subsequently, neurotoxicity was estimated from the integrated in vitro and kinetic studies. These results were compared with in vivo data from the literature on minimal neurotoxicity for these compounds, such as lowest-observed-effect levels (LOELs). The discrepancy between estimated and experimental LOELs ranged from 2- to 10-fold. LOEL estimates for compounds with a relatively low toxicity were more accurate than for compounds with a relatively high toxicity. LOELs for the most active compounds could only be established after consideration of additional in vitro results from the literature. The present study has generated encouraging results on the risk assessment of chemicals from in vitro studies and computer simulations and has identified some key directions for future research.
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| 9. |
- Delp, Johannes, et al.
(author)
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Neurotoxicity and underlying cellular changes of 21 mitochondrial respiratory chain inhibitors
- 2021
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In: Archives of Toxicology. - : Springer. - 0340-5761 .- 1432-0738. ; 95:2, s. 591-615
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Journal article (peer-reviewed)abstract
- Inhibition of complex I of the mitochondrial respiratory chain (cI) by rotenone and methyl-phenylpyridinium (MPP +) leads to the degeneration of dopaminergic neurons in man and rodents. To formally describe this mechanism of toxicity, an adverse outcome pathway (AOP:3) has been developed that implies that any inhibitor of cI, or possibly of other parts of the respiratory chain, would have the potential to trigger parkinsonian motor deficits. We used here 21 pesticides, all of which are described in the literature as mitochondrial inhibitors, to study the general applicability of AOP:3 or of in vitro assays that are assessing its activation. Five cI, three complex II (cII), and five complex III (cIII) inhibitors were characterized in detail in human dopaminergic neuronal cell cultures. The NeuriTox assay, examining neurite damage in LUHMES cells, was used as in vitro proxy of the adverse outcome (AO), i.e., of dopaminergic neurodegeneration. This test provided data on whether test compounds were unspecific cytotoxicants or specifically neurotoxic, and it yielded potency data with respect to neurite degeneration. The pesticide panel was also examined in assays for the sequential key events (KE) leading to the AO, i.e., mitochondrial respiratory chain inhibition, mitochondrial dysfunction, and disturbed proteostasis. Data from KE assays were compared to the NeuriTox data (AO). The cII-inhibitory pesticides tested here did not appear to trigger the AOP:3 at all. Some of the cI/cIII inhibitors showed a consistent AOP activation response in all assays, while others did not. In general, there was a clear hierarchy of assay sensitivity: changes of gene expression (biomarker of neuronal stress) correlated well with NeuriTox data; mitochondrial failure (measured both by a mitochondrial membrane potential-sensitive dye and a respirometric assay) was about 10-260 times more sensitive than neurite damage (AO); cI/cIII activity was sometimes affected at > 1000 times lower concentrations than the neurites. These data suggest that the use of AOP:3 for hazard assessment has a number of caveats: (i) specific parkinsonian neurodegeneration cannot be easily predicted from assays of mitochondrial dysfunction; (ii) deriving a point-of-departure for risk assessment from early KE assays may overestimate toxicant potency.
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| 10. |
- Forsby, A, et al.
(author)
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Polygodial induces inositol phosphate turnover in human neuroblastoma SH-SY5Y cells.
- 1996
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In: Neuroscience Letters. - 0304-3940 .- 1872-7972. ; 217:1, s. 50-4
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Journal article (peer-reviewed)abstract
- The pungent sesquiterpenoid unsaturated dialdehydes polygodial and isovelleral, have previously been shown to increase the intracellular free calcium concentration [Ca2+]i in human neuroblastoma SH-SY5Y cells, partly by a release from intracellular Ca2+ stores, whereas the non-pungent compound epipolygodial, had no effect on the [Ca2+]i. In this study, we investigated the effect of isovelleral, polygodial and epipolygodial on inositol phosphate (IP) formation on the assumption that there might be a correlation between the release of intracellular Ca2+ and pungency of the compounds. It was found that polygodial induced IP mobilization in a concentration dependent way, whereas isovelleral had no effect on the IP formation in the SH-SY5Y cells. Phosphoinositide (PPI) turnover was activated by epipolygodial, but only at concentrations 40-fold higher than for polygodial, which emphasizes the importance of the correct stereometry in the dialdehyde configuration for the biological activity of polygodial. The polygodial-induced formation of IP1 was reduced by 71% under extracellular calcium-free conditions, which suggests feedback interactions between the IP formation and the increase in [Ca2+]i to account for a periodic activation of phospholipase C(PLC).
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