TY - GEN A1 - Winkelbeiner, Nicola Lisa A1 - Wandt, Viktoria Klara Veronika A1 - Ebert, Franziska A1 - Lossow, Kristina A1 - Bankoglu, Ezgi E. A1 - Martin, Maximilian A1 - Mangerich, Aswin A1 - Stopper, Helga A1 - Bornhorst, Julia A1 - Kipp, Anna Patricia A1 - Schwerdtle, Tanja T1 - A Multi-Endpoint Approach to Base Excision Repair Incision Activity Augmented by PARylation and DNA Damage Levels in Mice BT - Impact of Sex and Age T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Investigation of processes that contribute to the maintenance of genomic stability is one crucial factor in the attempt to understand mechanisms that facilitate ageing. The DNA damage response (DDR) and DNA repair mechanisms are crucial to safeguard the integrity of DNA and to prevent accumulation of persistent DNA damage. Among them, base excision repair (BER) plays a decisive role. BER is the major repair pathway for small oxidative base modifications and apurinic/apyrimidinic (AP) sites. We established a highly sensitive non-radioactive assay to measure BER incision activity in murine liver samples. Incision activity can be assessed towards the three DNA lesions 8-oxo-2’-deoxyguanosine (8-oxodG), 5-hydroxy-2’-deoxyuracil (5-OHdU), and an AP site analogue. We applied the established assay to murine livers of adult and old mice of both sexes. Furthermore, poly(ADP-ribosyl)ation (PARylation) was assessed, which is an important determinant in DDR and BER. Additionally, DNA damage levels were measured to examine the overall damage levels. No impact of ageing on the investigated endpoints in liver tissue were found. However, animal sex seems to be a significant impact factor, as evident by sex-dependent alterations in all endpoints investigated. Moreover, our results revealed interrelationships between the investigated endpoints indicative for the synergetic mode of action of the cellular DNA integrity maintaining machinery. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1021 KW - maintenance of genomic integrity KW - ageing KW - sex KW - DNA damage KW - base excision repair (incision activity) KW - DNA damage response KW - poly(ADP-ribosyl)ation KW - liver Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-484831 SN - 1866-8372 IS - 1021 ER - TY - JOUR A1 - Winkelbeiner, Nicola Lisa A1 - Wandt, Viktoria Klara Veronika A1 - Ebert, Franziska A1 - Lossow, Kristina A1 - Bankoglu, Ezgi E. A1 - Martin, Maximilian A1 - Mangerich, Aswin A1 - Stopper, Helga A1 - Bornhorst, Julia A1 - Kipp, Anna Patricia A1 - Schwerdtle, Tanja T1 - A Multi-Endpoint Approach to Base Excision Repair Incision Activity Augmented by PARylation and DNA Damage Levels in Mice BT - Impact of Sex and Age JF - International Journal of Molecular Sciences N2 - Investigation of processes that contribute to the maintenance of genomic stability is one crucial factor in the attempt to understand mechanisms that facilitate ageing. The DNA damage response (DDR) and DNA repair mechanisms are crucial to safeguard the integrity of DNA and to prevent accumulation of persistent DNA damage. Among them, base excision repair (BER) plays a decisive role. BER is the major repair pathway for small oxidative base modifications and apurinic/apyrimidinic (AP) sites. We established a highly sensitive non-radioactive assay to measure BER incision activity in murine liver samples. Incision activity can be assessed towards the three DNA lesions 8-oxo-2’-deoxyguanosine (8-oxodG), 5-hydroxy-2’-deoxyuracil (5-OHdU), and an AP site analogue. We applied the established assay to murine livers of adult and old mice of both sexes. Furthermore, poly(ADP-ribosyl)ation (PARylation) was assessed, which is an important determinant in DDR and BER. Additionally, DNA damage levels were measured to examine the overall damage levels. No impact of ageing on the investigated endpoints in liver tissue were found. However, animal sex seems to be a significant impact factor, as evident by sex-dependent alterations in all endpoints investigated. Moreover, our results revealed interrelationships between the investigated endpoints indicative for the synergetic mode of action of the cellular DNA integrity maintaining machinery. KW - maintenance of genomic integrity KW - ageing KW - sex KW - DNA damage KW - base excision repair (incision activity) KW - DNA damage response KW - poly(ADP-ribosyl)ation KW - liver Y1 - 2020 U6 - https://doi.org/10.3390/ijms21186600 SN - 1422-0067 VL - 21 IS - 18 PB - Molecular Diversity Preservation International CY - Basel ER - TY - JOUR A1 - Meyer, Sören A1 - Raber, Georg A1 - Ebert, Franziska A1 - Taleshi, Mojtaba S. A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - Arsenic-containing hydrocarbons and arsenic-containing fatty acids: Transfer across and presystemic metabolism in the Caco-2 intestinal barrier model JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - Scope: Arsenic-containing hydrocarbons (AsHCs) and arsenic-containing fatty acids (AsFAs) represent two classes of arsenolipids occurring naturally in marine food. Toxicological data are yet scarce and an assessment regarding the risk to human health has not been possible. Here, we investigated the transfer and presystemic metabolism of five arsenolipids in an intestinal barrier model. Methods and results: Three AsHCs and two AsFAs were applied to the Caco-2 intestinal barrier model. Thereby, the short-chain AsHCs reached up to 50% permeability. Transport is likely to occur via passive diffusion. The AsFAs showed lower intestinal bioavailability, but respective permeabilities were still two to five times higher as compared to arsenobetaine or arsenosugars. Interestingly, AsFAs were effectively biotransformed while passing the in vitro intestinal barrier, whereas AsHCs were transported to the blood-facing compartment essentially unchanged. Conclusion: AsFAs can be presystemically metabolised and the amount of transferred arsenic is lower than that for AsHCs. In contrast, AsHCs are likely to be highly intestinally bioavailable to humans. Since AsHCs exert strong toxicity in vitro and in vivo, toxicity studies with experimental animals as well as a human exposure assessment are needed to assess the risk to human health related to the presence of AsHCs in seafood. KW - Arsenolipids KW - Caco-2 intestinal barrier model KW - Presystemic metabolism KW - Toxicity Y1 - 2015 U6 - https://doi.org/10.1002/mnfr.201500286 SN - 1613-4125 SN - 1613-4133 VL - 59 IS - 10 SP - 2044 EP - 2056 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Müller, Sandra Marie A1 - Ebert, Franziska A1 - Bornhorst, Julia A1 - Galla, Hans-Joachim A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - Arsenic-containing hydrocarbons disrupt a model in vitro blood-cerebrospinal fluid barrier JF - Journal of trace elements in medicine and biology N2 - Lipid-soluble arsenicals, so-called arsenolipids, have gained a lot of attention in the last few years because of their presence in many seafoods and reports showing substantial cytotoxicity emanating from arsenic-containing hydrocarbons (AsHCs), a prominent subgroup of the arsenolipids. More recent in vivo and in vitro studies indicate that some arsenolipids might have adverse effects on brain health. In the present study, we focused on the effects of selected arsenolipids and three representative metabolites on the blood-cerebrospinal fluid barrier (B-CSF-B), a brain-regulating interface. For this purpose, we incubated an in vitro model of the B-CSF-B composed of porcine choroid plexus epithelial cells (PCPECs) with three AsHCs, two arsenic-containing fatty acids (AsFAs) and three representative arsenolipid metabolites (dimethylarsinic acid, thio/oxo-dimethylpropanoic acid) to examine their cytotoxic potential and impact on barrier integrity. The toxic arsenic species arsenite was also tested in this way and served as a reference substance. While AsFAs and the metabolites showed no cytotoxic effects in the conducted assays, AsHCs showed a strong cytotoxicity, being up to 1.5-fold more cytotoxic than arsenite. Analysis of the in vitro B-CSF-B integrity showed a concentration dependent disruption of the barrier within 72 h. The correlation with the decreased plasma membrane surface area (measured as capacitance) indicates cytotoxic effects. These findings suggest exposure to elevated levels of certain arsenolipids may have detrimental consequences for the central nervous system. KW - Arsenolipids KW - Blood-liquor barrier KW - Blood-cerebrospinal fluid barrier KW - Arsenic-containing hydrocarbons KW - Arsenic-containing fatty acids Y1 - 2018 U6 - https://doi.org/10.1016/j.jtemb.2018.01.020 SN - 0946-672X VL - 49 SP - 171 EP - 177 PB - Elsevier GMBH CY - München ER - TY - JOUR A1 - Witt, Barbara A1 - Ebert, Franziska A1 - Meyer, Sören A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - Assessing neurodevelopmental effects of arsenolipids in pre-differentiated human neurons JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - Scope: In the general population exposure to arsenic occurs mainly via diet. Highest arsenic concentrations are found in seafood, where arsenic is present predominantly in its organic forms including arsenolipids. Since recent studies have provided evidence that arsenolipids could reach the brain of an organism and exert toxicity in fully differentiated human neurons, this work aims to assess the neurodevelopmental toxicity of arsenolipids. Methods and results: Neurodevelopmental effects of three arsenic-containing hydrocarbons (AsHC), two arsenic-containing fatty acids (AsFA), arsenite and dimethylarsinic acid (DMA(V)) were characterized in pre-differentiated human neurons. AsHCs and arsenite caused substantial cytotoxicity in a similar, low concentration range, whereas AsFAs and DMA(V) were less toxic. AsHCs were highly accessible for cells and exerted pronounced neurodevelopmental effects, with neurite outgrowth and the mitochondrial membrane potential being sensitive endpoints; arsenite did not substantially decrease those two endpoints. In fully differentiated neurons, arsenite and AsHCs caused neurite toxicity. Conclusion: These results indicate for a neurodevelopmental potential of AsHCs. Taken into account the possibility that AsHCs might easily reach the developing brain when exposed during early life, neurotoxicity and neurodevelopmental toxicity cannot be excluded. Further studies are needed in order to progress the urgently needed risk assessment. KW - Arsenic-containing fatty acids KW - Arsenic-containing hydrocarbons KW - Arsenite KW - Arsenolipids KW - Neurodevelopmental toxicity Y1 - 2017 U6 - https://doi.org/10.1002/mnfr.201700199 SN - 1613-4125 SN - 1613-4133 VL - 61 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Witt, Barbara A1 - Stiboller, Michael A1 - Raschke, Stefanie A1 - Friese, Sharleen A1 - Ebert, Franziska A1 - Schwerdtle, Tanja T1 - Characterizing effects of excess copper levels in a human astrocytic cell line with focus on oxidative stress markers JF - Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements, GMS N2 - Background: Being an essential trace element, copper is involved in diverse physiological processes. However, excess levels might lead to adverse effects. Disrupted copper homeostasis, particularly in the brain, has been associated with human diseases including the neurodegenerative disorders Wilson and Alzheimer?s disease. In this context, astrocytes play an important role in the regulation of the copper homeostasis in the brain and likely in the prevention against neuronal toxicity, consequently pointing them out as a potential target for the neurotoxicity of copper. Major toxic mechanisms are discussed to be directed against mitochondria probably via oxidative stress. However, the toxic potential and mode of action of copper in astrocytes is poorly understood, so far. Methods: In this study, excess copper levels affecting human astrocytic cell model and their involvement in the neurotoxic mode of action of copper, as well as, effects on the homeostasis of other trace elements (Mn, Fe, Ca and Mg) were investigated. Results: Copper induced substantial cytotoxic effects in the human astrocytic cell line following 48 h incubation (EC30: 250 ?M) and affected mitochondrial function, as observed via reduction of mitochondrial membrane potential and increased ROS production, likely originating from mitochondria. Moreover, cellular GSH metabolism was altered as well. Interestingly, not only cellular copper levels were affected, but also the homeostasis of other elements (Ca, Fe and Mn) were disrupted. Conclusion: One potential toxic mode of action of copper seems to be effects on the mitochondria along with induction of oxidative stress in the human astrocytic cell model. Moreover, excess copper levels seem to interact with the homeostasis of other essential elements such as Ca, Fe and Mn. Disrupted element homeostasis might also contribute to the induction of oxidative stress, likely involved in the onset and progression of neurodegenerative disorders. These insights in the toxic mechanisms will help to develop ideas and approaches for therapeutic strategies against copper-mediated diseases. KW - Copper KW - Astrocytes KW - Toxicity KW - Mitochondria KW - ROS KW - Trace elements Y1 - 2021 U6 - https://doi.org/10.1016/j.jtemb.2021.126711 SN - 1878-3252 VL - 65 PB - Elsevier CY - München ER - TY - JOUR A1 - Müller, Sandra Marie A1 - Ebert, Franziska A1 - Raber, Georg A1 - Meyer, Sören A1 - Bornhorst, Julia A1 - Hüwel, Stephan A1 - Galla, Hans-Joachim A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - Effects of arsenolipids on in vitro blood-brain barrier model JF - Archives of toxicology : official journal of EUROTOX N2 - Arsenic-containing hydrocarbons (AsHCs), a subgroup of arsenolipids (AsLs) occurring in fish and edible algae, possess a substantial neurotoxic potential in fully differentiated human brain cells. Previous in vivo studies indicating that AsHCs cross the blood–brain barrier of the fruit fly Drosophila melanogaster raised the question whether AsLs could also cross the vertebrate blood–brain barrier (BBB). In the present study, we investigated the impact of several representatives of AsLs (AsHC 332, AsHC 360, AsHC 444, and two arsenic-containing fatty acids, AsFA 362 and AsFA 388) as well as of their metabolites (thio/oxo-dimethylpropionic acid, dimethylarsinic acid) on porcine brain capillary endothelial cells (PBCECs, in vitro model for the blood–brain barrier). AsHCs exerted the strongest cytotoxic effects of all investigated arsenicals as they were up to fivefold more potent than the toxic reference species arsenite (iAsIII). In our in vitro BBB-model, we observed a slight transfer of AsHC 332 across the BBB after 6 h at concentrations that do not affect the barrier integrity. Furthermore, incubation with AsHCs for 72 h led to a disruption of the barrier at sub-cytotoxic concentrations. The subsequent immunocytochemical staining of three tight junction proteins revealed a significant impact on the cell membrane. Because AsHCs enhance the permeability of the in vitro blood–brain barrier, a similar behavior in an in vivo system cannot be excluded. Consequently, AsHCs might facilitate the transfer of accompanying foodborne toxicants into the brain. KW - Arsenolipids KW - Arsenic-containing hydrocarbons KW - Arsenic-containing fatty acids KW - In vitro blood-brain barrier model Y1 - 2017 SN - 0340-5761 SN - 1432-0738 VL - 92 IS - 2 SP - 823 EP - 832 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Ebert, Franziska A1 - Thomann, Marlies A1 - Witt, Barbara A1 - Müller, Sandra Marie A1 - Meyer, Sören A1 - Weber, Till A1 - Christmann, Markus A1 - Schwerdtle, Tanja T1 - Evaluating long-term cellular effects of the arsenic species thio-DMA(V): qPCR-based gene expression as screening tool JF - Journal of trace elements in medicine and biology N2 - Thio-dimethylarsinic acid (thio-DMA(V)) is a human urinary metabolite of the class 1 human carcinogen inorganic arsenic as well as of arsenosugars. Thio-DMA(V) exerts strong cellular toxicity, whereas its toxic modes of action are not fully understood. For the first time, this study characterises the impact of a long-term (21 days) in vitro incubation of thio-DMA(V) on the expression of selected genes related to cell death, stress response, epigenetics and DNA repair. The observed upregulation of DNMT1 might be a cellular compensation to counterregulate the in a very recent study observed massive global DNA hypomethylation after chronic thio-DMAv incubation. Moreover, our data suggest that chronic exposure towards subcytotoxic, pico- to nanomolar concentrations of thio-DMA(V) causes a stress response in human urothelial cells. The upregulation of genes encoding for proteins of DNA repair (Apex1,Lig1, XRCC1,DDB2, XPG, ATR) as well as damage response (GADD45A, GADD45G, Trp53) indicate a potential genotoxic risk emanating from thio-DMA(V) after long-term incubation. (C) 2016 Elsevier GmbH. All rights reserved. KW - Thio-dimethylarsinic acid KW - Long-term cellular toxicity KW - qPCR-based gene expression screening KW - GADD45A and GADD45G KW - DNMT1 KW - Cellular damage response Y1 - 2016 U6 - https://doi.org/10.1016/j.jtemb.2016.06.004 SN - 0946-672X VL - 37 SP - 78 EP - 84 PB - Yokohama Publishers CY - Jena ER - TY - JOUR A1 - Meyer, Sören A1 - Raber, Georg A1 - Ebert, Franziska A1 - Leffers, L. A1 - Mueller, Sandra Maria A1 - Taleshi, M. S. A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - In vitro toxicological characterisation of arsenic-containing fatty acids and three of their metabolites JF - Toxicology research N2 - Arsenic-containing fatty acids are a group of fat-soluble arsenic species (arsenolipids) which are present in marine fish and other seafood. Recently, it has been shown that arsenic-containing hydrocarbons, another group of arsenolipids, exert toxicity in similar concentrations comparable to arsenite although the toxic modes of action differ. Hence, a risk assessment of arsenolipids is urgently needed. In this study the cellular toxicity of a saturated (AsFA 362) and an unsaturated (AsFA 388) arsenic-containing fatty acid and three of their proposed metabolites (DMA(V), DMAPr and thio-DMAPr) were investigated in human liver cells (HepG2). Even though both arsenic-containing fatty acids were less toxic as compared to arsenic-containing hydrocarbons and arsenite, significant effects were observable at mu M concentrations. DMA(V) causes effects in a similar concentration range and it could be seen that it is metabolised to its highly toxic thio analogue thio-DMA(V) in HepG2 cells. Nevertheless, DMAPr and thio-DMAPr did not exert any cytotoxicity. In summary, our data indicate that risks to human health related to the presence of arsenic-containing fatty acids in marine food cannot be excluded. This stresses the need for a full in vitro and in vivo toxicological characterisation of these arsenolipids. Y1 - 2015 U6 - https://doi.org/10.1039/c5tx00122f SN - 2045-452X SN - 2045-4538 VL - 4 IS - 5 SP - 1289 EP - 1296 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Meyer, Sören A1 - Matissek, M. A1 - Mueller, S. M. A1 - Taleshi, M. S. A1 - Ebert, Franziska A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - In vitro toxicological characterisation of three arsenic-containing hydrocarbons JF - Metallomics : integrated biometal science N2 - Arsenic-containing hydrocarbons are one group of fat-soluble organic arsenic compounds (arsenolipids) found in marine fish and other seafood. A risk assessment of arsenolipids is urgently needed, but has not been possible because of the total lack of toxicological data. In this study the cellular toxicity of three arsenic-containing hydrocarbons was investigated in cultured human bladder (UROtsa) and liver (HepG2) cells. Cytotoxicity of the arsenic-containing hydrocarbons was comparable to that of arsenite, which was applied as the toxic reference arsenical. A large cellular accumulation of arsenic, as measured by ICP-MS/MS, was observed after incubation of both cell lines with the arsenolipids. Moreover, the toxic mode of action shown by the three arsenic-containing hydrocarbons seemed to differ from that observed for arsenite. Evidence suggests that the high cytotoxic potential of the lipophilic arsenicals results from a decrease in the cellular energy level. This first in vitro based risk assessment cannot exclude a risk to human health related to the presence of arsenolipids in seafood, and indicates the urgent need for further toxicity studies in experimental animals to fully assess this possible risk. Y1 - 2014 U6 - https://doi.org/10.1039/c4mt00061g SN - 1756-5901 SN - 1756-591X VL - 6 IS - 5 SP - 1023 EP - 1033 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Frede, Katja A1 - Ebert, Franziska A1 - Kipp, Anna Patricia A1 - Schwerdtle, Tanja A1 - Baldermann, Susanne T1 - Lutein Activates the Transcription Factor Nrf2 in Human Retinal Pigment Epithelial Cells JF - Journal of agricultural and food chemistry : a publication of the American Chemical Society N2 - The degeneration of the retinal pigment epithelium caused by oxidative damage is a stage of development in age related macular degeneration (AMD). The carotenoid lutein is a major macular pigment that may reduce the incidence and progression of AMD, but the underlying mechanism is currently not fully understood. Carotenoids are known to be direct antioxidants. However, carotenoids can also activate cellular pathways resulting in indirect antioxidant effects. Here, we investigate the influence of lutein on the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) target genes in human retinal pigment epithelial cells (ARPE-19 cells) using lutein-loaded Tween40 micelles. The micelles were identified as a suitable delivery system since they were nontoxic in APRE-19 cells up to 0.04% Tween40 and led to a cellular lutein accumulation of 62 mu M +/- 14 mu M after 24 h. Lutein significantly enhanced Nrf2 translocation to the nucleus 1.5 +/- 0.4-fold compared to that of unloaded micelles after 4 h. Furthermore, lutein treatment for 24 h significantly increased the transcripts of NAD(P)H:quinone oxidoreductase 1 (NQO1) by 1.7 +/- 0.1-fold, glutamate-cysteine ligase regulatory subunit (GCLm) by 1.4 +/- 0.1-fold, and heme oxygenase-1 (HO-1) by 1.8 +/- 0.3-fold. Moreover, we observed a significant enhancement of NQO1 activity by 1.2 +/- 0.1-fold. Collectively, this study indicates that lutein not only serves as a direct antioxidant but also activates Nrf 2 in ARPE-19 cells. KW - lutein KW - Nif2 KW - ARPE-19 cells KW - AMD KW - Tween40 micelles Y1 - 2017 U6 - https://doi.org/10.1021/acs.jafc.7b01929 SN - 0021-8561 SN - 1520-5118 VL - 65 SP - 5944 EP - 5952 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Pieper, Imke A1 - Wehe, Christoph A. A1 - Bornhorst, Julia A1 - Ebert, Franziska A1 - Leffers, Larissa A1 - Holtkamp, Michael A1 - Hoeseler, Pia A1 - Weber, Till A1 - Mangerich, Aswin A1 - Buerkle, Alexander A1 - Karst, Uwe A1 - Schwerdtle, Tanja T1 - Mechanisms of Hg species induced toxicity in cultured human astrocytes: genotoxicity and DNA-damage response JF - Metallomics : integrated biometal science N2 - The toxicologically most relevant mercury (Hg) species for human exposure is methylmercury (MeHg). Thiomersal is a common preservative used in some vaccine formulations. The aim of this study is to get further mechanistic insight into the yet not fully understood neurotoxic modes of action of organic Hg species. Mercury species investigated include MeHgCl and thiomersal. Additionally HgCl2 was studied, since in the brain mercuric Hg can be formed by dealkylation of the organic species. As a cellular system astrocytes were used. In vivo astrocytes provide the environment necessary for neuronal function. In the present study, cytotoxic effects of the respective mercuricals increased with rising alkylation level and correlated with their cellular bioavailability. Further experiments revealed for all species at subcytotoxic concentrations no induction of DNA strand breaks, whereas all species massively increased H2O2-induced DNA strand breaks. This co- genotoxic effect is likely due to a disturbance of the cellular DNA damage response. Thus, at nanomolar, sub-cytotoxic concentrations, all three mercury species strongly disturbed poly(ADP-ribosyl)ation, a signalling reaction induced by DNA strand breaks. Interestingly, the molecular mechanism behind this inhibition seems to be different for the species. Since chronic PARP-1 inhibition is also discussed to sacrifice neurogenesis and learning abilities, further experiments on neurons and in vivo studies could be helpful to clarify whether the inhibition of poly(ADP-ribosyl) ation contributes to organic Hg induced neurotoxicity. Y1 - 2014 U6 - https://doi.org/10.1039/c3mt00337j SN - 1756-5901 SN - 1756-591X VL - 6 IS - 3 SP - 662 EP - 671 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Nicolai, Merle Marie A1 - Witt, Barbara A1 - Friese, Sharleen A1 - Michaelis, Vivien A1 - Hölz-Armstrong, Lisa A1 - Martin, Maximilian A1 - Ebert, Franziska A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Mechanistic studies on the adverse effects of manganese overexposure in differentiated LUHMES cells JF - Food and chemical toxicology N2 - Manganese (Mn) is an essential trace element, but overexposure is associated with toxicity and neurological dysfunction. Accumulation of Mn can be observed in dopamine-rich regions of the brain in vivo and Mn-induced oxidative stress has been discussed extensively. Nevertheless, Mn-induced DNA damage, adverse effects of DNA repair, and possible resulting consequences for the neurite network are not yet characterized. For this, LUHMES cells were used, as they differentiate into dopaminergic-like neurons and form extensive neurite networks. Experiments were conducted to analyze Mn bioavailability and cytotoxicity of MnCl2, indicating a dose-dependent uptake and substantial cytotoxic effects. DNA damage, analyzed by means of 8-oxo-7,8-dihydro-2'-guanine (8oxodG) and single DNA strand break formation, showed significant dose- and time-dependent increase of DNA damage upon 48 h Mn exposure. Furthermore, the DNA damage response was increased which was assessed by analytical quantification of poly(ADP-ribosyl)ation (PARylation). Gene expression of the respective DNA repair genes was not significantly affected. Degradation of the neuronal network is significantly altered by 48 h Mn exposure. Altogether, this study contributes to the characterization of Mn-induced neurotoxicity, by analyzing the adverse effects of Mn on genome integrity in dopaminergic-like neurons and respective outcomes. KW - Manganese KW - Dopaminergic neurons KW - DNA integrity KW - DNA repair KW - Neurodegeneration KW - Oxidative stress KW - Genotoxicity Y1 - 2022 U6 - https://doi.org/10.1016/j.fct.2022.112822 SN - 0278-6915 SN - 1873-6351 VL - 161 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Werno, Martin Witold A1 - Wilhelmi, Ilka A1 - Kuropka, Benno A1 - Ebert, Franziska A1 - Freund, Christian A1 - Schürmann, Annette T1 - The GTPase ARFRP1 affects lipid droplet protein composition and triglyceride release from intracellular storage of intestinal Caco-2 cells JF - Biochemical and biophysical research communications N2 - Intestinal release of dietary triglycerides via chylomicrons is the major contributor to elevated postprandial triglyceride levels. Dietary lipids can be transiently stored in cytosolic lipid droplets (LDs) located in intestinal enterocytes for later release. ADP ribosylation factor-related protein 1 (ARFRP1) participates in processes of LD growth in adipocytes and in lipidation of lipoproteins in liver and intestine. This study aims to explore the impact of ARFRP1 on LD organization and its interplay with chylomicron-mediated triglyceride release in intestinal-like Caco-2 cells. Suppression of Arfrp1 reduced release of intracellularly derived triglycerides (0.69-fold) and increased the abundance of transitional endoplasmic reticulum ATPase TERA/VCP, fatty acid synthase-associated factor 2 (FAF2) and perilipin 2 (Plin2) at the LD surface. Furthermore, TERA/VCP and FAF2 co-occurred more frequently with ATGL at LDs, suggesting a reduced adipocyte triglyceride lipase (ATGL)-mediated lipolysis. Accordingly, inhibition of lipolysis reduced lipid release from intracellular storage pools by the same magnitude as Arfrp1 depletion. Thus, the lack of Arfrp1 increases the abundance of lipolysis-modulating enzymes TERA/VCP, FAF2 and Plin2 at LDs, which might decrease lipolysis and reduce availability of fatty acids for triglyceride synthesis and their release via chylomicrons. (C) 2018 The Authors. Published by Elsevier Inc. KW - Chylomicron KW - Lipid droplet proteome KW - Triglyceride secretion KW - Lipolysis Y1 - 2018 U6 - https://doi.org/10.1016/j.bbrc.2018.10.092 SN - 0006-291X SN - 1090-2104 VL - 506 IS - 1 SP - 259 EP - 265 PB - Elsevier CY - San Diego 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 - 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 - 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 - 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 - 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 - CHAP A1 - Wandt, Viktoria Klara Veronika A1 - Winkelbeiner, Nicola A1 - Loßow, Kristina A1 - Kopp, Johannes A1 - Simon, Luise A1 - Ebert, Franziska A1 - Kipp, Anna Patricia A1 - Schwerdtle, Tanja T1 - Trace elements, ageing, and sex. Impact on genome stability BT - Abstracts of the 87th Annual Meeting of the German Society for Experimental and Clinical Pharmacology and Toxicology (DGPT) with contribution of the Arbeitsgemeinschaft für Angewandte Humanpharmakologie e. V. (AGAH) T2 - Naunyn-Schmiedeberg's archives of pharmacology Y1 - 2021 U6 - https://doi.org/10.1007/s00210-021-02066-6 SN - 0028-1298 SN - 1432-1912 VL - 394 IS - Suppl. 1 SP - S13 EP - S13 PB - Springer CY - Berlin ; Heidelberg ER -