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 - TY - JOUR A1 - Ruszkiewicz, Joanna A. A1 - de Macedo, Gabriel Teixeira A1 - Miranda-Vizuete, Antonio A1 - Teixeira da Rocha, Joao B. A1 - Bowman, Aaron B. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Aschner, Michael T1 - The cytoplasmic thioredoxin system in Caenorhabditis elegans affords protection from methylmercury in an age-specific manner JF - Neurotoxicology : the interdisciplinary journal of effects to toxic substances on the nervous system N2 - Methylmercury (MeHg) is an environmental pollutant linked to many neurological defects, especially in developing individuals. The thioredoxin (TRX) system is a key redox regulator affected by MeHg toxicity, however the mechanisms and consequences of MeHg-induced dysfunction are not completely understood. This study evaluated the role of the TRX system in C. elegans susceptibility to MeHg during development. Worms lacking or overexpressing proteins from the TRX family were exposed to MeHg for 1 h at different developmental stage: L1, L4 and adult. Worms without cytoplasmic thioredoxin system exhibited age-specific susceptibility to MeHg when compared to wild-type (wt). This susceptibility corresponded partially to decreased total glutathione (GSH) levels and enhanced degeneration of dopaminergic neurons. In contrast, the overexpression of the cytoplasmic system TRX-1/TRXR-1 did not provide substantial protection against MeHg. Moreover, transgenic worms exhibited decreased protein expression for cytoplasmic thioredoxin reductase (TRXR-1). Both mitochondrial thioredoxin system TRX-2/TRXR-2, as well as other thioredoxin-like proteins: TRX-3, TRX-4, TRX-5 did not show significant role in C. elegans resistance to MeHg. Based on the current findings, the cytoplasmic thioredoxin system TRX-1/TRXR-1 emerges as an important age-sensitive protectant against MeHg toxicity in C. elegans. KW - Methylmercury KW - Age KW - Development KW - C. elegans KW - Thioredoxin KW - Thioredoxin reductase Y1 - 2018 U6 - https://doi.org/10.1016/j.neuro.2018.08.007 SN - 0161-813X SN - 1872-9711 VL - 68 SP - 189 EP - 202 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lohren, Hanna A1 - Bornhorst, Julia A1 - Galla, Hans-Joachim A1 - Schwerdtle, Tanja T1 - The blood–cerebrospinal fluid barrier BT - First evidence for an active transport of organic mercury compounds out of the brain JF - Metallomics : integrated biometal science N2 - Exposure to organic mercury compounds promotes primarily neurological effects. Although methylmercury is recognized as a potent neurotoxicant, its transfer into the central nervous system (CNS) is not fully evaluated. While methylmercury and thiomersal pass the blood–brain barrier, limited data are available regarding the second brain regulating interface, the blood–cerebrospinal fluid (CSF) barrier. This novel study was designed to investigate the effects of organic as well as inorganic mercury compounds on, and their transfer across, a porcine in vitro model of the blood–CSF barrier for the first time. The barrier system is significantly more sensitive towards organic Hg compounds as compared to inorganic compounds regarding the endpoints cytotoxicity and barrier integrity. Whereas there are low transfer rates from the blood side to the CSF side, our results strongly indicate an active transfer of the organic mercury compounds out of the CSF. These results are the first to demonstrate an efflux of organic mercury compounds regarding the CNS and provide a completely new approach in the understanding of mercury compounds specific transport. Y1 - 2015 U6 - https://doi.org/10.1039/C5MT00171D SN - 1756-5901 SN - 1756-591X VL - 10 IS - 7 SP - 1420 EP - 1430 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Lohren, Hanna A1 - Bornhorst, Julia A1 - Galla, Hans-Joachim A1 - Schwerdtle, Tanja T1 - The blood-cerebrospinal fluid barrier - first evidence for an active transport of organic mercury compounds out of the brain JF - Metallomics : integrated biometal science N2 - Exposure to organic mercury compounds promotes primarily neurological effects. Although methylmercury is recognized as a potent neurotoxicant, its transfer into the central nervous system (CNS) is not fully evaluated. While methylmercury and thiomersal pass the blood-brain barrier, limited data are available regarding the second brain regulating interface, the blood-cerebrospinal fluid (CSF) barrier. This novel study was designed to investigate the effects of organic as well as inorganic mercury compounds on, and their transfer across, a porcine in vitro model of the blood-CSF barrier for the first time. The barrier system is significantly more sensitive towards organic Hg compounds as compared to inorganic compounds regarding the endpoints cytotoxicity and barrier integrity. Whereas there are low transfer rates from the blood side to the CSF side, our results strongly indicate an active transfer of the organic mercury compounds out of the CSF. These results are the first to demonstrate an efflux of organic mercury compounds regarding the CNS and provide a completely new approach in the understanding of mercury compounds specific transport. Y1 - 2015 U6 - https://doi.org/10.1039/c5mt00171d SN - 1756-5901 SN - 1756-591X VL - 7 IS - 10 SP - 1420 EP - 1430 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Taleshi, Mojtaba S. A1 - Seidler-Egdal, Rune K. A1 - Jensen, Kenneth Bendix A1 - Schwerdtle, Tanja A1 - Francesconi, Kevin A. T1 - Synthesis and Characterization of Arsenolipids: Naturally Occurring Arsenic Compounds in Fish and Algae JF - Organometallics N2 - Arsenic-containing lipids (arsenolipids) are natural products present in fish and algae. Because these compounds occur in foods, there is considerable interest in their human toxicology. We report the synthesis and characterization of seven arsenic-containing lipids, including six natural products. The compounds comprise dimethylarsinyl groups attached to saturated long-chain hydrocarbons (three compounds), saturated long-chain fatty acids (two compounds), and monounsaturated long chain fatty acids (two compounds). The arsenic group was introduced through sodium dimethylarsenide or bis(dimethylarsenic) oxide. The latter route provided higher and more reproducible yields, and consequently, this pathway was followed to synthesize six of the seven compounds. Mass spectral properties are described to assist in the identification of these compounds in natural samples. The pure synthesized arsenolipids will be used for in vitro experiments with human cells to test their uptake, biotransformation, and possible toxic effects. Y1 - 2014 U6 - https://doi.org/10.1021/om4011092 SN - 0276-7333 SN - 1520-6041 VL - 33 IS - 6 SP - 1397 EP - 1403 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Witt, Barbara A1 - Schaumlöffel, Dirk A1 - Schwerdtle, Tanja T1 - Subcellular Localization of Copper BT - Cellular Bioimaging with Focus on Neurological Disorders JF - International Journal of Molecular Sciences N2 - As an essential trace element, copper plays a pivotal role in physiological body functions. In fact, dysregulated copper homeostasis has been clearly linked to neurological disorders including Wilson and Alzheimer’s disease. Such neurodegenerative diseases are associated with progressive loss of neurons and thus impaired brain functions. However, the underlying mechanisms are not fully understood. Characterization of the element species and their subcellular localization is of great importance to uncover cellular mechanisms. Recent research activities focus on the question of how copper contributes to the pathological findings. Cellular bioimaging of copper is an essential key to accomplish this objective. Besides information on the spatial distribution and chemical properties of copper, other essential trace elements can be localized in parallel. Highly sensitive and high spatial resolution techniques such as LA-ICP-MS, TEM-EDS, S-XRF and NanoSIMS are required for elemental mapping on subcellular level. This review summarizes state-of-the-art techniques in the field of bioimaging. Their strengths and limitations will be discussed with particular focus on potential applications for the elucidation of copper-related diseases. Based on such investigations, further information on cellular processes and mechanisms can be derived under physiological and pathological conditions. Bioimaging studies might enable the clarification of the role of copper in the context of neurodegenerative diseases and provide an important basis to develop therapeutic strategies for reduction or even prevention of copper-related disorders and their pathological consequences. KW - copper KW - cellular bioimaging KW - neurodegenerative diseases KW - copper-related disorders KW - SIMS techniques KW - TEM KW - S-XRF Y1 - 2020 U6 - https://doi.org/10.3390/ijms21072341 SN - 1422-0067 VL - 21 IS - 7 PB - Molecular Diversity Preservation International CY - Basel ER - TY - JOUR A1 - Kotthoff, Lisa A1 - O'Callaghan, Sarah-Louise A1 - Lisec, Jan A1 - Schwerdtle, Tanja A1 - Koch, Matthias T1 - Structural annotation of electro- and photochemically generated transformation products of moxidectin using high-resolution mass spectrometry JF - Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry, Analusis and Quimica analitica N2 - Moxidectin (MOX) is a widely used anthelmintic drug for the treatment of internal and external parasites in food-producing and companion animals. Transformation products (TPs) of MOX, formed through metabolic degradation or acid hydrolysis, may pose a potential environmental risk, but only few were identified so far. In this study, we therefore systematically characterized electro- and photochemically generated MOX TPs using high-resolution mass spectrometry (HRMS). Oxidative electrochemical (EC) TPs were generated in an electrochemical reactor and photochemical (PC) TPs by irradiation with UV-C light. Subsequent HRMS measurements were performed to identify accurate masses and deduce occurring modification reactions of derived TPs in a suspected target analysis. In total, 26 EC TPs and 59 PC TPs were found. The main modification reactions were hydroxylation, (de-)hydration, and derivative formation with methanol for EC experiments and isomeric changes, (de-)hydration, and changes at the methoxime moiety for PC experiments. In addition, several combinations of different modification reactions were identified. For 17 TPs, we could predict chemical structures through interpretation of acquired MS/MS data. Most modifications could be linked to two specific regions of MOX. Some previously described metabolic reactions like hydroxylation or O-demethylation were confirmed in our EC and PC experiments as reaction type, but the corresponding TPs were not identical to known metabolites or degradation products. The obtained knowledge regarding novel TPs and reactions will aid to elucidate the degradation pathway of MOX which is currently unknown. KW - veterinary drug KW - moxidectin KW - transformation products KW - electrochemistry KW - photochemistry KW - LC KW - HRMS Y1 - 2020 U6 - https://doi.org/10.1007/s00216-020-02572-1 SN - 1618-2642 SN - 1618-2650 VL - 412 IS - 13 SP - 3141 EP - 3152 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Peres, Tanara V. A1 - Horning, Kyle J. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Bowman, Aaron B. A1 - Aschner, Michael T1 - Small Molecule Modifiers of In Vitro Manganese Transport Alter Toxicity In Vivo JF - Biological Trace Element Research N2 - Manganese (Mn) is essential for several species and daily requirements are commonly met by an adequate diet. Mn overload may cause motor and psychiatric disturbances and may arise from an impaired or not fully developed excretion system, transporter malfunction and/or exposure to excessive levels of Mn. Therefore, deciphering processes regulating neuronal Mn homeostasis is essential to understand the mechanisms of Mn neurotoxicity. In the present study, we selected two small molecules (with opposing effects on Mn transport) from a previous high throughput screen of 40,167 to test their effects on Mn toxicity parameters in vivo using Caenorhabditis elegans. We pre-exposed worms to VU0063088 and VU0026921 for 30min followed by co-exposure for 1h with Mn and evaluated Mn accumulation, dopaminergic (DAergic) degeneration and worm survival. Control worms were exposed to vehicle (DMSO) and saline only. In pdat-1::GFP worms, with GFP labeled DAergic neurons, we observed a decrease of Mn-induced DAergic degeneration in the presence of both small molecules. This effect was also observed in an smf-2 knockout strain. SMF-2 is a regulator of Mn transport in the worms and this strain accumulates higher Mn levels. We did not observe improved survival in the presence of small molecules. Our results suggest that both VU0063088 and VU0026921 may modulate Mn levels in the worms through a mechanism that does not require SMF-2 and induce protection against Mn neurotoxicity. KW - Small molecules KW - Manganese KW - Neurotoxicity KW - C. elegans KW - Dopamine Y1 - 2018 U6 - https://doi.org/10.1007/s12011-018-1531-7 SN - 0163-4984 SN - 1559-0720 VL - 188 IS - 1 SP - 127 EP - 134 PB - Human press inc. CY - Totowa ER - TY - JOUR A1 - Meyer, Sören A1 - Lopez-Serrano, Aniceto A1 - Mitze, Hanna A1 - Jakubowski, Norbert A1 - Schwerdtle, Tanja T1 - Single-cell analysis by ICP-MS/MS as a fast tool for cellular bioavailability studies of arsenite JF - Metallomics : integrated biometal science N2 - Single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS) has become a powerful and fast tool to evaluate the elemental composition at a single-cell level. In this study, the cellular bioavailability of arsenite (incubation of 25 and 50 mu M for 0-48 h) has been successfully assessed by SC-ICP-MS/MS for the first time directly after re-suspending the cells in water. This procedure avoids the normally arising cell membrane permeabilization caused by cell fixation methods (e.g. methanol fixation). The reliability and feasibility of this SC-ICP-MS/MS approach with a limit of detection of 0.35 fg per cell was validated by conventional bulk ICP-MS/MS analysis after cell digestion and parallel measurement of sulfur and phosphorus. Y1 - 2017 U6 - https://doi.org/10.1039/c7mt00285h SN - 1756-5901 SN - 1756-591X VL - 10 IS - 1 SP - 73 EP - 76 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Rohn, Isabelle A1 - Kroepfl, Nina A1 - Bornhorst, Julia A1 - Kühnelt, Doris A1 - Schwerdtle, Tanja T1 - Side-directed transfer and presystemic metabolism of selenoneine in a human intestinal barrier model JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - Scope: Selenoneine, a recently discovered selenium (Se) species mainly present in marine fish, is the Se analogue of ergothioneine, a sulfur-containing purported antioxidant. Although similar properties have been proposed for selenoneine, data on its relevance to human health are yet scarce. Here, the transfer and presystemic metabolism of selenoneine in an in vitro model of the human intestinal barrier are investigated. Methods and results: Selenoneine and the reference species Se-methylselenocysteine (MeSeCys) and selenite are applied to the Caco-2 intestinal barrier model. Selenoneine is transferred in higher amounts, but with similar kinetics as selenite, while MeSeCys shows the highest permeability. In contrast to the reference species, transfer of selenoneine is directed toward the blood side. Cellular Se contents demonstrate that selenoneine is efficiently taken up by Caco-2 cells. Moreover, HPLC/MS-based Se speciation studies reveal a partial metabolism to Se-methylselenoneine, a metabolite previously detected in human blood and urine. Conclusions: Selenoneine is likely to pass the intestinal barrier via transcellular, carrier-mediated transport, is highly bioavailable to Caco-2 cells and undergoes metabolic transformations. Therefore, further studies are needed to elucidate its possible health effects and to characterize the metabolism of selenoneine in humans. KW - bioavailability KW - Caco-2 intestinal barrier model KW - presystemic metabolism KW - selenoneine KW - Se-methylselenoneine Y1 - 2019 U6 - https://doi.org/10.1002/mnfr.201900080 SN - 1613-4125 SN - 1613-4133 VL - 63 IS - 12 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Ruszkiewicz, Joanna A. A1 - de Macedo, Gabriel Teixeira A1 - Miranda-Vizuete, Antonio A1 - Bowman, Aaron B. A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Antunes Soares, Felix A. A1 - Aschner, Michael T1 - Sex-Specific response of caenorhabditis elegans to Methylmercury Toxicity JF - Neurotoxicity Research N2 - Methylmercury (MeHg), an abundant environmental pollutant, has long been known to adversely affect neurodevelopment in both animals and humans. Several reports from epidemiological studies, as well as experimental data indicate sex-specific susceptibility to this neurotoxicant; however, the molecular bases of this process are still not clear. In the present study, we used Caenorhabditis elegans (C. elegans), to investigate sex differences in response to MeHg toxicity during development. Worms at different developmental stage (L1, L4, and adult) were treated with MeHg for 1h. Lethality assays revealed that male worms exhibited significantly higher resistance to MeHg than hermaphrodites, when at L4 stage or adults. However, the number of worms with degenerated neurons was unaffected by MeHg, both in males and hermaphrodites. Lower susceptibility of males was not related to changes in mercury (Hg) accumulation, which was analogous for both wild-type (wt) and male-rich him-8 strain. Total glutathione (GSH) levels decreased upon MeHg in him-8, but not in wt. Moreover, the sex-dependent response of the cytoplasmic thioredoxin system was observedmales exhibited significantly higher expression of thioredoxin TRX-1, and thioredoxin reductase TRXR-1 expression was downregulated upon MeHg treatment only in hermaphrodites. These outcomes indicate that the redox status is an important contributor to sex-specific sensitivity to MeHg in C. elegans. KW - Methylmercury KW - Sex KW - Male KW - C KW - elegans KW - Antioxidant KW - Thioredoxin Y1 - 2019 U6 - https://doi.org/10.1007/s12640-018-9949-4 SN - 1029-8428 SN - 1476-3524 VL - 35 IS - 1 SP - 208 EP - 216 PB - Springer CY - New York ER -