TY - JOUR A1 - Baesler, Jessica A1 - Kopp, Johannes Florian A1 - Pohl, Gabriele A1 - Aschner, Michael A1 - Haase, Hajo A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Zn homeostasis in genetic models of Parkinson’s disease in Caenorhabditis elegans JF - Journal of Trace Elements in Medicine and Biology N2 - While the underlying mechanisms of Parkinson’s disease (PD) are still insufficiently studied, a complex interaction between genetic and environmental factors is emphasized. Nevertheless, the role of the essential trace element zinc (Zn) in this regard remains controversial. In this study we altered Zn balance within PD models of the versatile model organism Caenorhabditis elegans (C. elegans) in order to examine whether a genetic predisposition in selected genes with relevance for PD affects Zn homeostasis. Protein-bound and labile Zn species act in various areas, such as enzymatic catalysis, protein stabilization pathways and cell signaling. Therefore, total Zn and labile Zn were quantitatively determined in living nematodes as individual biomarkers of Zn uptake and bioavailability with inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) or a multi-well method using the fluorescent probe ZinPyr-1. Young and middle-aged deletion mutants of catp-6 and pdr-1, which are orthologues of mammalian ATP13A2 (PARK9) and parkin (PARK2), showed altered Zn homeostasis following Zn exposure compared to wildtype worms. Furthermore, age-specific differences in Zn uptake were observed in wildtype worms for total as well as labile Zn species. These data emphasize the importance of differentiation between Zn species as meaningful biomarkers of Zn uptake as well as the need for further studies investigating the role of dysregulated Zn homeostasis in the etiology of PD. KW - Caenorhabditis elegans KW - Zinc KW - Zinc homeostasis KW - Parkinson disease KW - Labile zinc Y1 - 2019 U6 - https://doi.org/10.1016/j.jtemb.2019.05.005 VL - 55 SP - 44 EP - 49 PB - Elsevier CY - München ER - TY - JOUR A1 - Baesler, Jessica A1 - Kopp, Johannes F. A1 - Pohl, Gabriele A1 - Aschner, Michael A1 - Haase, Hajo A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Zn homeostasis in genetic models of Parkinson’s disease in Caenorhabditis elegans JF - Journal of trace elements in medicine and biology KW - Caenorhabditis elegans KW - Zinc KW - Zinc homeostasis KW - Parkinson disease KW - Labile zinc Y1 - 2019 U6 - https://doi.org/10.1016/j.jtemb.2019.05.005 SN - 0946-672X VL - 55 SP - 44 EP - 49 PB - Elsevier GMBH CY - München ER - TY - JOUR A1 - Köhler, Yvonne A1 - Luther, Eva Maria A1 - Meyer, Sören A1 - Schwerdtle, Tanja A1 - Dringen, Ralf T1 - Uptake and toxicity of arsenite and arsenate in cultured brain astrocytes JF - Journal of trace elements in medicine and biology N2 - Inorganic arsenicals are environmental toxins that have been connected with neuropathies and impaired cognitive functions. To investigate whether such substances accumulate in brain astrocytes and affect their viability and glutathione metabolism, we have exposed cultured primary astrocytes to arsenite or arsenate. Both arsenicals compromised the cell viability of astrocytes in a time- and concentration-dependent manner. However, the early onset of cell toxicity in arsenite-treated astrocytes revealed the higher toxic potential of arsenite compared with arsenate. The concentrations of arsenite and arsenate that caused within 24 h half-maximal release of the cytosolic enzyme lactate dehydrogenase were around 0.3 mM and 10 mM, respectively. The cellular arsenic contents of astrocytes increased rapidly upon exposure to arsenite or arsenate and reached after 4 h of incubation almost constant steady state levels. These levels were about 3-times higher in astrocytes that had been exposed to a given concentration of arsenite compared with the respective arsenate condition. Analysis of the intracellular arsenic species revealed that almost exclusively arsenite was present in viable astrocytes that had been exposed to either arsenate or arsenite. The emerging toxicity of arsenite 4 h after exposure was accompanied by a loss in cellular total glutathione and by an increase in the cellular glutathione disulfide content. These data suggest that the high arsenite content of astrocytes that had been exposed to inorganic arsenicals causes an increase in the ratio of glutathione disulfide to glutathione which contributes to the toxic potential of these substances. KW - Arsenic KW - Astrocytes KW - GSH KW - Metabolism KW - Toxicity Y1 - 2014 U6 - https://doi.org/10.1016/j.jtemb.2014.04.007 SN - 0946-672X VL - 28 IS - 3 SP - 328 EP - 337 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Kumar, Kevin K. A1 - Goodwin, Cody R. A1 - Uhouse, Michael A. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Aschner, Michael A. A1 - McLean, John A. A1 - Bowman, Aaron B. T1 - Untargeted metabolic profiling identifies interactions between Huntington's disease and neuronal manganese status JF - Metallomics N2 - Manganese (Mn) is an essential micronutrient for development and function of the nervous system. Deficiencies in Mn transport have been implicated in the pathogenesis of Huntington's disease (HD), an autosomal dominant neurodegenerative disorder characterized by loss of medium spiny neurons of the striatum. Brain Mn levels are highest in striatum and other basal ganglia structures, the most sensitive brain regions to Mn neurotoxicity. Mouse models of HD exhibit decreased striatal Mn accumulation and HD striatal neuron models are resistant to Mn cytotoxicity. We hypothesized that the observed modulation of Mn cellular transport is associated with compensatory metabolic responses to HD pathology. Here we use an untargeted metabolomics approach by performing ultraperformance liquid chromatography-ion mobility-mass spectrometry (UPLC-IM-MS) on control and HD immortalized mouse striatal neurons to identify metabolic disruptions under three Mn exposure conditions, low (vehicle), moderate (non-cytotoxic) and high (cytotoxic). Our analysis revealed lower metabolite levels of pantothenic acid, and glutathione (GSH) in HD striatal cells relative to control cells. HD striatal cells also exhibited lower abundance and impaired induction of isobutyryl carnitine in response to increasing Mn exposure. In addition, we observed induction of metabolites in the pentose shunt pathway in HD striatal cells after high Mn exposure. These findings provide metabolic evidence of an interaction between the HD genotype and biologically relevant levels of Mn in a striatal cell model with known HD by Mn exposure interactions. The metabolic phenotypes detected support existing hypotheses that changes in energetic processes underlie the pathobiology of both HD and Mn neurotoxicity. KW - hallervorden-spatz-syndrome KW - mobility-mass spectrometry KW - energy-metabolism KW - coenzyme-a KW - model KW - neurotoxicity KW - glutathione KW - database KW - cells KW - neurodegeneration Y1 - 2015 U6 - https://doi.org/10.1039/C4MT00223G SN - 1756-591X SN - 1756-5901 VL - 7 SP - 363 EP - 370 PB - RSC Publ. CY - Cambridge ER - TY - JOUR A1 - Kumar, Kevin K. A1 - Goodwin, Cody R. A1 - Uhouse, Michael A. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Aschner, Michael A. A1 - McLean, John A. A1 - Bowman, Aaron B. T1 - Untargeted metabolic profiling identifies interactions between JF - Metallomics : integrated biometal science Y1 - 2015 U6 - https://doi.org/10.1039/c4mt00223g SN - 1756-5901 SN - 1756-591X VL - 7 IS - 2 SP - 363 EP - 370 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Rohn, Isabelle A1 - Raschke, Stefanie A1 - Aschner, Michael A1 - Tuck, Simon A1 - Kuehnelt, Doris A1 - Kipp, Anna Patricia A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Treatment of caenorhabditis elegans with small selenium species enhances antioxidant defense systems JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - ScopeSmall selenium (Se) species play a key role in Se metabolism and act as dietary sources of the essential trace element. However, they are redox-active and trigger pro- and antioxidant responses. As health outcomes are strongly species-dependent, species-specific characteristics of Se compounds are tested in vivo. Methods and resultsIn the model organism Caenorhabditis elegans (C. elegans), immediate and sustained effects of selenite, selenomethionine (SeMet), and Se-methylselenocysteine (MeSeCys) are studied regarding their bioavailability, incorporation into proteins, as well as modulation of the cellular redox status. While all tested Se compounds are bioavailable, only SeMet persistently accumulates and is non-specifically incorporated into proteins. However, the protection toward chemically-induced formation of reactive species is independent of the applied Se compound. Increased thioredoxin reductase (TXNRD) activity and changes in mRNA expression levels of antioxidant proteins indicate the activation of cellular defense mechanisms. However, in txnrd-1 deletion mutants, no protective effects of the Se species are observed anymore, which is also reflected by differential gene expression data. ConclusionSe species protect against chemically-induced reactive species formation. The identified immediate and sustained systemic effects of Se species give rise to speculations on possible benefits facing subsequent periods of inadequate Se intake. KW - antioxidant defense systems KW - caenorhabditis elegans KW - selenium KW - oxidative stress KW - selenoproteins Y1 - 2019 U6 - https://doi.org/10.1002/mnfr.201801304 SN - 1613-4125 SN - 1613-4133 VL - 63 IS - 9 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Marschall, Talke Anu A1 - Kroepfl, Nina A1 - Jensen, Kenneth Bendix A1 - Bornhorst, Julia A1 - Meermann, B. A1 - Kühnelt, Doris A1 - Schwerdtle, Tanja T1 - Tracing cytotoxic effects of small organic Se species in human liver cells back to total cellular Se and Se metabolites JF - Metallomics N2 - Small selenium (Se) species play a major role in the metabolism, excretion and dietary supply of the essential trace element selenium. Human cells provide a valuable tool for investigating currently unresolved issues on the cellular mechanisms of Se toxicity and metabolism. In this study, we developed two isotope dilution inductively coupled plasma tandem-mass spectrometry based methods and applied them to human hepatoma cells (HepG2) in order to quantitatively elucidate total cellular Se concentrations and cellular Se species transformations in relation to the cytotoxic effects of four small organic Se species. Species-and incubation time-dependent results were obtained: the two major urinary excretion metabolites trimethylselenonium (TMSe) and methyl-2-acetamido-2-deoxy-1-seleno-beta- D-galactopyranoside (SeSugar 1) were taken up by the HepG2 cells in an unmodified manner and did not considerably contribute to the Se pool. In contrast, Se-methylselenocysteine (MeSeCys) and selenomethionine (SeMet) were taken up in higher amounts, they were largely incorporated by the cells (most likely into proteins) and metabolized to other small Se species. Two new metabolites of MeSeCys, namely gamma-glutamyl-Se-methylselenocysteine and Se-methylselenoglutathione, were identified by means of HPLC-electrospray-ionization-Orbitrap-MS. They are certainly involved in the (de-) toxification modes of Se metabolism and require further investigation. Y1 - 2017 U6 - https://doi.org/10.1039/c6mt00300a SN - 1756-5901 SN - 1756-591X VL - 9 SP - 268 EP - 277 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Ebert, Franziska A1 - Meyer, Sören A1 - Leffers, Larissa A1 - Raber, Georg A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - Toxicological characterisation of a thio-arsenosugar-glycerol in human cells JF - Journal of trace elements in medicine and biology N2 - Arsenosugars are water-soluble arsenic species predominant in marine algae and other seafood including mussels and oysters. They typically occur at levels ranging from 2 to 50 mg arsenic/kg dry weight. Most of the arsenosugars contain arsenic as a dimethylarsinoyl group (Me2As(O)-), commonly referred to as the oxo forms, but thio analogues have also been identified in marine organisms and as metabolic products of oxo-arsenosugars. So far, no data regarding toxicity and toxicokinetics of thio-arsenosugars are available. This in vitro-based study indicates that thio-dimethylarsenosugar-glycerol exerts neither pronounced cytotoxicity nor genotoxicity even though this arsenical was bioavailable to human hepatic (HepG2) and urothelial (UROtsa) cells. Experiments with the Caco-2 intestinal barrier model mimicking human absorption indicate for the thio-arsenosugar-glycerol higher intestinal bioavailability as compared to the oxo-arsenosugars. Nevertheless, absorption estimates were much lower in comparison to other arsenicals including arsenite and arsenic-containing hydrocarbons. Arsenic speciation in cell lysates revealed that HepG2 cells are able to metabolise the thio-arsenosugar-glycerol to some extent to dimethylarsinic acid (DMA). These first in vitro data cannot fully exclude risks to human health related to the presence of thio-arsenosugars in food. (C) 2016 Elsevier GmbH. All rights reserved. KW - Arsenic KW - Thio-arsenosugar-glycerol KW - Toxicity KW - Toxicokinetics KW - Genotoxicity KW - Metabolism Y1 - 2016 U6 - https://doi.org/10.1016/j.jtemb.2016.04.013 SN - 0946-672X VL - 38 SP - 150 EP - 156 PB - Springer Publishing Company CY - Jena ER - TY - JOUR A1 - Finke, Hannah A1 - Wandt, Viktoria Klara Veronika A1 - Ebert, Franziska A1 - Guttenberger, Nikolaus A1 - Glabonjat, Ronald A. A1 - Stiboller, Michael A1 - Francesconi, Kevin A. A1 - Raber, Georg A1 - Schwerdtle, Tanja T1 - Toxicological assessment of arsenic-containing phosphatidylcholines in HepG2 cells N2 - Arsenolipids include a wide range of organic arsenic species that occur naturally in seafood and thereby contribute to human arsenic exposure. Recently arsenic-containing phosphatidylcholines (AsPCs) were identified in caviar, fish, and algae. In this first toxicological assessment of AsPCs, we investigated the stability of both the oxo- and thioxo-form of an AsPC under experimental conditions, and analyzed cell viability, indicators of genotoxicity and biotransformation in human liver cancer cells (HepG2). Precise toxicity data could not be obtained owing to the low solubility in the cell culture medium of the thioxo-form, and the ease of hydrolysis of the oxo-form, and to a lesser degree the thioxo-form. Hydrolysis resulted amongst others in the respective constituent arsenic-containing fatty acid (AsFA). Incubation of the cells with oxo-AsPC resulted in a toxicity similar to that determined for the hydrolysis product oxo-AsFA alone, and there were no indices for genotoxicity. Furthermore, the oxo-AsPC was readily taken up by the cells resulting in high cellular arsenic concentrations (50 μM incubation: 1112 ± 146 μM As cellular), whereas the thioxo-AsPC was substantially less bioavailable (50 μM incubation: 293 ± 115 μM As cellular). Speciation analysis revealed biotransformation of the AsPCs to a series of AsFAs in the culture medium, and, in the case of the oxo-AsPC, to as yet unidentified arsenic species in cell pellets. The results reveal the difficulty of toxicity studies of AsPCs in vitro, indicate that their toxicity might be largely governed by their arsenic fatty acid content and suggest a multifaceted human metabolism of food derived complex arsenolipids. KW - Biochemistry KW - Biological Sciences KW - Science and Mathematics KW - Books KW - Journals Y1 - 2020 U6 - https://doi.org/10.1039/d0mt00073f VL - 12 IS - 7 SP - 1159 EP - 1170 PB - Oxford University CY - Cambridge ER - TY - JOUR A1 - Witt, Barbara A1 - Meyer, Sören A1 - Ebert, Franziska A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - Toxicity of two classes of arsenolipids and their water-soluble metabolites in human differentiated neurons JF - Archives of toxicology : official journal of EUROTOX N2 - Arsenolipids are lipid-soluble organoarsenic compounds, mainly occurring in marine organisms, with arsenic-containing hydrocarbons (AsHCs) and arsenic-containing fatty acids (AsFAs) representing two major subgroups. Recently, toxicity studies of several arsenolipids showed a high cytotoxic potential of those arsenolipids in human liver and bladder cells. Furthermore, feeding studies with Drosophila melanogaster indicated an accumulation of arsenolipids in the fruit fly’s brain. In this study, the neurotoxic potential of three AsHCs, two AsFAs and three metabolites (dimethylarsinic acid, thio/oxo-dimethylarsenopropanoic acid) was investigated in comparison to the toxic reference arsenite (iAsIII) in fully differentiated human brain cells (LUHMES cells). Thereby, in the case of AsHCs both the cell number and cell viability were reduced in a low micromolar concentration range comparable to iAsIII, while AsFAs and the applied metabolites were less toxic. Mechanistic studies revealed that AsHCs reduced the mitochondrial membrane potential, whereas neither iAsIII nor AsFAs had an impact. Furthermore, neurotoxic mechanisms were investigated by examining the neuronal network. Here, AsHCs massively disturbed the neuronal network and induced apoptotic effects, while iAsIII and AsFAs showed comparatively lesser effects. Taking into account the substantial in vitro neurotoxic potential of the AsHCs and the fact that they could transfer across the physiological barriers of the brain, a neurotoxic potential in vivo for the AsHCs cannot be excluded and needs to be urgently characterized. KW - Arsenolipids KW - Neurons KW - Cytotoxicity KW - Neurotoxicity KW - Arsenic-containing hydrocarbons KW - Arsenic-containing fatty acids Y1 - 2017 U6 - https://doi.org/10.1007/s00204-017-1933-x SN - 0340-5761 SN - 1432-0738 VL - 91 SP - 3121 EP - 3134 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Bornhorst, Julia A1 - Ebert, Franziska A1 - Meyer, Sören A1 - Ziemann, Vanessa A1 - Xiong, Chan A1 - Guttenberger, Nikolaus A1 - Raab, Andrea A1 - Baesler, Jessica A1 - Aschner, Michael A1 - Feldmann, Jörg A1 - Francesconi, Kevin A1 - Raber, Georg A1 - Schwerdtle, Tanja T1 - Toxicity of three types of arsenolipids BT - species-specific effects in Caenorhabditis elegans JF - Metallomics N2 - Although fish and seafood are well known for their nutritional benefits, they contain contaminants that might affect human health. Organic lipid-soluble arsenic species, so called arsenolipids, belong to the emerging contaminants in these food items; their toxicity has yet to be systematically studied. Here, we apply the in vivo model Caenorhabditis elegans to assess the effects of two arsenic-containing hydrocarbons (AsHC), a saturated arsenic-containing fatty acid (AsFA), and an arsenic-containing triacylglyceride (AsTAG) in a whole organism. Although all arsenolipids were highly bioavailable in Caenorhabditis elegans, only the AsHCs were substantially metabolized to thioxylated or shortened metabolic products and induced significant toxicity, affecting both survival and development. Furthermore, the AsHCs were several fold more potent as compared to the toxic reference arsenite. This study clearly indicates the need for a full hazard identification of subclasses of arsenolipids to assess whether they pose a risk to human health. Y1 - 2020 U6 - https://doi.org/https://doi.org/10.1039/d0mt00039f SN - 1756-591X SN - 1756-5901 VL - 12 IS - 5 SP - 794 EP - 798 PB - Oxford University Press CY - Cambridge ER - TY - JOUR A1 - Lohren, Hanna A1 - Blagojevic, Lara A1 - Fitkau, Romy A1 - Ebert, Franziska A1 - Schildknecht, Stefan A1 - Leist, Marcel A1 - Schwerdtle, Tanja T1 - Toxicity of organic and inorganic mercury species in human neurons and human astrocytes JF - Journal of trace elements in medicine and biology N2 - Organic mercury (Hg) species exert their toxicity primarily in the central nervous system. The food relevant Hg species methylmercury (MeHg) has been frequently studied regarding its neurotoxic effects in vitro and in vivo. Neurotoxicity of thiomersal, which is used as a preservative in medical preparations, is to date less characterised. Due to dealkylation of organic Hg or oxidation of elemental Hg, inorganic Hg is present in the brain albeit these species are not able to readily cross the blood brain barrier. This study compared for the first time toxic effects of organic MeHg chloride (MeHgCl) and thiomersal as well as inorganic mercury chloride (HgCl2) in differentiated human neurons (LUHMES) and human astrocytes (CCF-STTG1). The three Hg species differ in their degree and mechanism of toxicity in those two types of brain cells. Generally, neurons are more susceptible to Hg species induced cytotoxicity as compared to astrocytes. This might be due to the massive cellular mercury uptake in the differentiated neurons. The organic compounds exerted stronger cytotoxic effects as compared to inorganic HgCl2. In contrast to HgCl2 exposure, organic Hg compounds seem to induce the apoptotic cascade in neurons following low-level exposure. No indicators for apoptosis were identified for both inorganic and organic mercury species in astrocytes. Our studies clearly demonstrate species-specific toxic mechanisms. A mixed exposure towards all Hg species in the brain can be assumed. Thus, prospectively coexposure studies as well as cocultures of neurons and astrocytes could provide additional information in the investigation of Hg induced neurotoxicity. KW - Methylmercury KW - Thiomersal KW - Mercuric mercury KW - Human differentiated neurons KW - Cytotoxicity KW - Apoptosis Y1 - 2015 U6 - https://doi.org/10.1016/j.jtemb.2015.06.008 SN - 0946-672X VL - 32 SP - 200 EP - 208 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Unterberg, Marlies A1 - Leffers, Larissa A1 - Hübner, Florian A1 - Humpf, Hans-Ulrich A1 - Lepikhov, Konstantin A1 - Walter, Jörn A1 - Ebert, Franziska A1 - Schwerdtle, Tanja T1 - Toxicity of arsenite and thio-DMAV after long-term (21 days) incubation of human urothelial cells: cytotoxicity, genotoxicity and epigenetics JF - Toxicology Research N2 - This study aims to further mechanistically understand toxic modes of action after chronic inorganic arsenic exposure. Therefore long-term incubation studies in cultured cells were carried out, to display chronically attained changes, which cannot be observed in the generally applied in vitro short-term incubation studies. Particularly, the cytotoxic, genotoxic and epigenetic effects of an up to 21 days incubation of human urothelial (UROtsa) cells with pico- to nanomolar concentrations of iAsIII and its metabolite thio-DMAV were compared. After 21 days of incubation, cytotoxic effects were strongly enhanced in the case of iAsIII and might partly be due to glutathione depletion and genotoxic effects on the chromosomal level. These results are in strong contrast to cells exposed to thio-DMAV. Thus, cells seemed to be able to adapt to this arsenical, as indicated among others by an increase in the cellular glutathione level. Most interestingly, picomolar concentrations of both iAsIII and thio-DMAV caused global DNA hypomethylation in UROtsa cells, which was quantified in parallel by 5-medC immunostaining and a newly established, reliable, high resolution mass spectrometry (HRMS)-based test system. This is the first time that epigenetic effects are reported for thio-DMAV; iAsIII induced epigenetic effects occur in at least 8000 fold lower concentrations as reported in vitro before. The fact that both arsenicals cause DNA hypomethylation at really low, exposure-relevant concentrations in human urothelial cells suggests that this epigenetic effect might contribute to inorganic arsenic induced carcinogenicity, which for sure has to be further investigated in future studies. KW - induced malignant-transformation KW - genomic dna methylation KW - vitro toxicological characterization KW - thio-dimethylarsinic acid KW - bladder-cancer KW - methyltransferases dnmt3a KW - cytosine methylation KW - carcinogen exposure KW - mass-spectrometry KW - gene-expression Y1 - 2014 SN - 2045-4538 SN - 2045-452X VL - 3 IS - 6 SP - 456 EP - 464 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Unterberg, Marlies A1 - Leffers, Larissa A1 - Huebner, Florian A1 - Humpf, Hans-Ulrich A1 - Lepikhov, Konstantin A1 - Walter, Joern A1 - Ebert, Franziska A1 - Schwerdtle, Tanja T1 - Toxicity of arsenite and thio-DMA(V) after long-term (21 days) incubation of human urothelial cells: cytotoxicity, genotoxicity and epigenetics JF - Toxicology research N2 - This study aims to further mechanistically understand toxic modes of action after chronic inorganic arsenic exposure. Therefore long-term incubation studies in cultured cells were carried out, to display chronically attained changes, which cannot be observed in the generally applied in vitro short-term incubation studies. Particularly, the cytotoxic, genotoxic and epigenetic effects of an up to 21 days incubation of human urothelial (UROtsa) cells with pico- to nanomolar concentrations of iAs(III) and its metabolite thio-DMA(V) were compared. After 21 days of incubation, cytotoxic effects were strongly enhanced in the case of iAs(III) and might partly be due to glutathione depletion and genotoxic effects on the chromosomal level. These results are in strong contrast to cells exposed to thio-DMA(V). Thus, cells seemed to be able to adapt to this arsenical, as indicated among others by an increase in the cellular glutathione level. Most interestingly, picomolar concentrations of both iAs(III) and thio-DMA(V) caused global DNA hypomethylation in UROtsa cells, which was quantified in parallel by 5-medC immunostaining and a newly established, reliable, high resolution mass spectrometry (HRMS)-based test system. This is the first time that epigenetic effects are reported for thio-DMA(V); iAs(III) induced epigenetic effects occur in at least 8000 fold lower concentrations as reported in vitro before. The fact that both arsenicals cause DNA hypomethylation at really low, exposure-relevant concentrations in human urothelial cells suggests that this epigenetic effect might contribute to inorganic arsenic induced carcinogenicity, which for sure has to be further investigated in future studies. Y1 - 2014 U6 - https://doi.org/10.1039/c4tx00036f SN - 2045-452X SN - 2045-4538 VL - 3 IS - 6 SP - 456 EP - 464 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Strehlau, Jenny A1 - Weber, Till A1 - Luerenbaum, Constantin A1 - Bornhorst, Julia A1 - Galla, Hans-Joachim A1 - Schwerdtle, Tanja A1 - Winter, Martin A1 - Nowak, Sascha T1 - Towards quantification of toxicity of lithium ion battery electrolytes - development and validation of a liquid-liquid extraction GC-MS method for the determination of organic carbonates in cell culture materials JF - Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry, Analusis and Quimica analitica N2 - A novel method based on liquid-liquid extraction with subsequent gas chromatography separation and mass spectrometric detection (GC-MS) for the quantification of organic carbonates in cell culture materials is presented. Method parameters including the choice of extraction solvent, of extraction method and of extraction time were optimised and the method was validated. The setup allowed for determination within a linear range of more than two orders of magnitude. The limits of detection (LODs) were between 0.0002 and 0.002 mmol/L and the repeatability precisions were in the range of 1.5-12.9%. It could be shown that no matrix effects were present and recovery rates between 98 and 104% were achieved. The methodology was applied to cell culture models incubated with commercial lithium ion battery (LIB) electrolytes to gain more insight into the potential toxic effects of these compounds. The stability of the organic carbonates in cell culture medium after incubation was studied. In a porcine model of the blood-cerebrospinal fluid (CSF) barrier, it could be shown that a transfer of organic carbonates into the brain facing compartment took place. KW - Liquid-liquid extraction KW - GC-MS KW - Lithiumion battery (LIB) KW - Organic carbonates KW - Cell culture materials Y1 - 2017 U6 - https://doi.org/10.1007/s00216-017-0549-6 SN - 1618-2642 SN - 1618-2650 VL - 409 SP - 6123 EP - 6131 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Hackethal, Christin A1 - Kopp, Johannes Florian A1 - Sarvan, Irmela A1 - Schwerdtle, Tanja A1 - Lindtner, Oliver T1 - Total arsenic and water-soluble arsenic species in foods of the first German total diet study (BfR MEAL Study) JF - Food chemistry N2 - Arsenic can occur in foods as inorganic and organic forms. Inorganic arsenic is more toxic than most watersoluble organic arsenic compounds such as arsenobetaine, which is presumed to be harmless for humans. Within the first German total diet study, total arsenic, inorganic arsenic, arsenobetaine, dimethylarsinic acid and monomethylarsonic acid were analyzed in various foods. Highest levels of total arsenic were found in fish, fish products and seafood (mean: 1.43 mg kg(-1); n = 39; min-max: 0.01-6.15 mg kg(-1)), with arsenobetaine confirmed as the predominant arsenic species (1.233 mg kg 1; n = 39; min-max: 0.01-6.23 mg kg (1)). In contrast, inorganic arsenic was determined as prevalent arsenic species in terrestrial foods (0.02 mg kg (1); n = 38; min-max: 0-0.11 mg kg (1)). However, the toxicity of arsenic species varies and measurements are necessary to gain information about the composition and changes of arsenic species in foods due to household processing of foods. KW - Occurrence data KW - Food KW - Total arsenic KW - Arsenic speciation KW - Inductively KW - coupled plasma mass spectrometry Y1 - 2021 U6 - https://doi.org/10.1016/j.foodchem.2020.128913 SN - 0308-8146 SN - 1873-7072 VL - 346 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Draude, F. A1 - Pelster, A. A1 - Koersgen, M. A1 - Kassenboehmer, R. A1 - Schwerdtle, Tanja A1 - Muething, J. A1 - Arlinghaus, H. F. T1 - ToF-SIMS imaging of plasma membrane lipids with sub-micrometer resolution JF - Surface and interface analysis : an international journal devoted to the development and application of techniques for the analysis surfaces, interfaces and thin films N2 - Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used for label-free analyses of the molecular lateral distribution of two different epithelial cell membranes (PANC-1 and UROtsa). The goal of the research was to enhance the ion yield of specific membrane molecules for improving the membrane imaging capability of ToF-SIMS on the nanoscale lateral dimension. For this task, a special silicon wafer sandwich preparation technique was optimized using different wafer materials, spacers, and washing procedures. Under optimized preparation conditions, the yield could be significantly enhanced, allowing imaging of the inhomogeneous distribution of phosphocholine (common head group for phosphatidylcholine and sphingomyelin) of a PANC-1 cell membrane's outer lipid layer with a lateral resolution of less than 200nm. Copyright (c) 2014 John Wiley & Sons, Ltd. KW - ToF-SIMS KW - high-resolution imaging KW - membrane analysis KW - lipid analysis KW - yield enhancement KW - sample preparation Y1 - 2014 U6 - https://doi.org/10.1002/sia.5576 SN - 0142-2421 SN - 1096-9918 VL - 46 SP - 127 EP - 130 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Dünkelberg, Sophie A1 - Maywald, Martina A1 - Schmitt, Anne Kristina A1 - Schwerdtle, Tanja A1 - Meyer, Sören A1 - Rink, Lothar T1 - The interaction of sodium and zinc in the priming of T cell subpopulations regarding Th17 and Treg cells JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - Scope: Nutrition is a critical determinant of a functional immune system. The aim of this study is to investigate the molecular mechanisms by which immune cells are influenced by zinc and sodium. Methods and Results: Mixed lymphocyte cultures and Jurkat cells are generated and incubated with zinc, sodium, or a combination of both for further tests. Zinc induces the number of regulatory T cells (Treg) and decreases T helper 17 cells (Th17), and sodium has the opposite effect. The transforming growth factor beta receptor signaling pathway is also enhanced by zinc and reduced by sodium as indicated by contrary phosphoSmad 2/3 induction. Antagonistic effects can also be seen on zinc transporter and metallothionein-1 (MT-1) mRNA expression: zinc declines Zip10 mRNA expression while sodium induces it, whereas MT-1 mRNA expression is induced by zinc while it is reduced by sodium. Conclusion: This data indicate that zinc and sodium display opposite effects regarding Treg and Th17 induction in MLC, respectively, resulting in a contrary effect on the immune system. Additionally, it reveals a direct interaction of zinc and sodium in the priming of T cell subpopulations and shows that Zip10 and MT-1 play a significant role in those differentiation pathways. KW - Foxp3 KW - regulatory T cells KW - sodium KW - T helper 17 cells KW - zinc Y1 - 2020 U6 - https://doi.org/10.1002/mnfr.201900245 SN - 1613-4133 VL - 64 IS - 2 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Cramer, Sandra A1 - Tacke, Sebastian A1 - Bornhorst, Julia A1 - Klingauf, Jürgen A1 - Schwerdtle, Tanja A1 - Galla, Hans-Joachim T1 - The Influence of Silver Nanoparticles on the Blood-Brain and the Blood-Cerebrospinal Fluid Barrier in vitro JF - Journal of Nanomedicine & Nanotechnology N2 - The use of silver nanoparticles in medical and consumer products such as wound dressings, clothing and cosmetic has increased significantly in recent years. Still, the influence of these particles on our health and especially on our brain, has not been examined adequately up to now. We studied the influence of AgEO- (Ethylene Oxide) and AgCitrate-Nanoparticles (NPs) on the protective barriers of the brain, namely the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (blood-CSF) barrier in vitro. The NPs toxicity was evaluated by examining changes in membrane integrity, cell morphology, barrier properties, oxidative stress and inflammatory reactions. AgNPs decreased cell viability, disturbed barrier integrity and tight junctions and triggered oxidative stress and DNA strand breaks. However, all mentioned effects were, at least partly, suppressed by a Citrate-coating and were most pronounced in the cells of the BBB as compared to the epithelial cells representing the blood-CSF barrier. AgEO- but not AgCitrate-NPs also triggered an inflammatory reaction in porcine brain capillary endothelial cells (PBCEC), which represent the BBB. Our data indicate that AgNPs may cause adverse effects within the barriers of the brain, but their toxicity can be reduced by choosing an appropriate coating material. Y1 - 2014 U6 - https://doi.org/10.4172/2157-7439.1000225 SN - 2157-7439 VL - 5 IS - 5 ER - TY - JOUR A1 - Maares, Maria A1 - Duman, Ayse A1 - Keil, Claudia A1 - Schwerdtle, Tanja A1 - Haase, Hajo T1 - The impact of apical and basolateral albumin on intestinal zinc resorption in the Caco-2/HT-29-MTX co-culture model JF - Metallomics : integrated biometal science N2 - The molecular mechanisms of intestinal zinc resorption and its regulation are still topics of ongoing research. To this end, the application of suitable in vitro intestinal models, optimized with regard to their cellular composition and medium constituents, is of crucial importance. As one vital aspect, the impact of cell culture media or buffer compounds, respectively, on the speciation and cellular availability of zinc has to be considered when investigating zinc resorption. Thus, the present study aims to investigate the impact of serum, and in particular its main constituent serum albumin, on zinc uptake and toxicity in the intestinal cell line Caco-2. Furthermore, the impact of serum albumin on zinc resorption is analyzed using a co-culture of Caco-2 cells and the mucin-producing goblet cell line HT-29-MTX. Apically added albumin significantly impaired zinc uptake into enterocytes and buffered its cytotoxicity. Yet, undigested albumin does not occur in the intestinal lumen in vivo and impairment of zinc uptake was abrogated by digestion of albumin. Interestingly, zinc uptake, as well as gene expression studies of mt1a and selected intestinal zinc transporters after zinc incubation for 24 h, did not show significant differences between 0 and 10% serum. Importantly, the basolateral application of serum in a transport study significantly enhanced fractional apical zinc resorption, suggesting that the occurrence of a zinc acceptor in the plasma considerably affects intestinal zinc resorption. This study demonstrates that the apical and basolateral medium composition is crucial when investigating zinc, particularly its intestinal resorption, using in vitro cell culture. Y1 - 2018 U6 - https://doi.org/10.1039/c8mt00064f SN - 1756-5901 SN - 1756-591X VL - 10 IS - 7 SP - 979 EP - 991 PB - Royal Society of Chemistry CY - Cambridge ER -