@article{DraudeKoersgenPelsteretal.2015, author = {Draude, Felix and K{\"o}rsgen, Martin and Pelster, Andreas and Schwerdtle, Tanja and M{\"u}thing, Johannes and Arlinghaus, Heinrich F.}, title = {Characterization of freeze-fractured epithelial plasma membranes on nanometer scale with ToF-SIMS}, series = {Analytical \& bioanalytical chemistry}, volume = {407}, journal = {Analytical \& bioanalytical chemistry}, number = {8}, publisher = {Springer}, address = {Heidelberg}, issn = {1618-2642}, doi = {10.1007/s00216-014-8334-2}, pages = {2203 -- 2211}, year = {2015}, abstract = {Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to characterize the freeze-fracturing process of human epithelial PANC-1 and UROtsa cells. For this purpose, phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, and phosphatidylserine standard samples were investigated to find specific signals with both high specificity and signal intensity. The results were used to investigate single cells of subconfluent cell layers prepared with a special silicon wafer sandwich preparation technique. This freeze-fracturing technique strips cell membranes off the cells, isolating them on opposing silicon wafer substrates. Criteria were found for defining regions with stripped off cell membranes and, on the opposing wafer, complementary regions with the remaining cells. Measured ethanolamine/choline and serine/choline ratios in these regions clearly showed that in the freeze-fracturing process, the lipid bilayer of the plasma membrane is split along its central zone. Accordingly, only the outer lipid monolayer is stripped off the cell, while the inner lipid monolayer remains attached to the cell on the opposing wafer, thus allowing detailed analysis of a single lipid monolayer. Furthermore, it could be shown that using different washing procedures did not influence the transmembrane lipid distribution. Under optimized preparation conditions, it became feasible to detect lipids with a lateral resolution of approximately 100 nm. The data indicate that ToF-SIMS would be a very useful technique to study with very high lateral resolution changes in lipid composition caused, for example, by lipid storage diseases or pharmaceuticals that interfere with the lipid metabolism.}, language = {en} } @article{EbertZiemannWandtetal.2020, author = {Ebert, Franziska and Ziemann, Vanessa and Wandt, Viktoria Klara Veronika and Witt, Barbara and M{\"u}ller, Sandra Marie and Guttenberger, Nikolaus and Bankoglu, Ezgi Eyluel and Stopper, Helga and Raber, Georg and Francesconi, Kevin A. and Schwerdtle, Tanja}, title = {Cellular toxicological characterization of a thioxolated arsenic-containing hydrocarbon}, series = {Journal of trace elements in medicine and biology}, volume = {61}, journal = {Journal of trace elements in medicine and biology}, publisher = {Elsevier}, address = {M{\"u}nchen}, doi = {10.1016/j.jtemb.2020.126563}, year = {2020}, abstract = {Arsenolipids, especially arsenic-containing hydrocarbons (AsHC), are an emerging class of seafood originating contaminants. Here we toxicologically characterize a recently identified oxo-AsHC 332 metabolite, thioxo-AsHC 348 in cultured human liver (HepG2) cells. Compared to results of previous studies of the parent compound oxo-AsHC 332, thioxo-AsHC 348 substantially affected cell viability in the same concentration range but exerted about 10-fold lower cellular bioavailability. Similar to oxo-AsHC 332, thioxo-AsHC 348 did not substantially induce oxidative stress nor DNA damage. Moreover, in contrast to oxo-AsHC 332 mitochondria seem not to be a primary subcellular toxicity target for thioxo-AsHC 348. This study indicates that thioxo-AsHC 348 is at least as toxic as its parent compound oxo-AsHC 332 but very likely acts via a different mode of toxic action, which still needs to be identified.}, language = {en} } @article{HenzeHomannRohnetal.2016, author = {Henze, Andrea and Homann, Thomas and Rohn, Isabelle and Aschner, Michael A. and Link, Christopher D. and Kleuser, Burkhard and Schweigert, Florian J. and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep37346}, pages = {12}, year = {2016}, abstract = {The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time-and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.}, language = {en} } @article{HenzeHomannRohnetal.2016, author = {Henze, Andrea and Homann, Thomas and Rohn, Isabelle and Aschner, Michael A. and Link, Christopher D. and Kleuser, Burkhard and Schweigert, Florian J. and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep37346}, pages = {12}, year = {2016}, abstract = {The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.}, language = {en} } @article{PieperMarekUnterbergetal.2014, author = {Pieper, Christian and Marek, Jasmin Jacqueline and Unterberg, Marlies and Schwerdtle, Tanja and Galla, Hans-Joachim}, title = {Brain capillary pericytes contribute to the immune defense in response to cytokines or LPS in vitro}, series = {Brain research : an international multidisciplinary journal devoted to fundamental research in the brain sciences}, volume = {1550}, journal = {Brain research : an international multidisciplinary journal devoted to fundamental research in the brain sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0006-8993}, doi = {10.1016/j.brainres.2014.01.004}, pages = {1 -- 8}, year = {2014}, abstract = {The prevention of an inflammation in the brain is one of the most important goals the body has to achieve. As pericytes are located on the abluminal side of the capillaries in the brain, their role in fighting against invading pathogens has been investigated in some points, mostly in their ability to behave like macrophages. Here we studied the potential of pericytes to react as immune cells under inflammatory conditions, especially regarding the expression of the inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), major histocompatibility complex II (MHC II) molecules, CD68, as well as the generation of reactive oxygen and nitrogen species (RONS), and their ability in phagocytosis. Quantitative real time PCR and western blot analysis showed that pericytes are able to increase the expression of typical inflammatory marker proteins after the stimulation with tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1 beta), interferon-gamma (IFN-gamma), or lipopolysaccharides (LPS). Depending on the different specific pro-inflammatory factors pericytes changed the expression of alpha smooth muscle actin (alpha SMA), the most predominant pericyte marker. We conclude that the role of the pericytes within the immune system is regulated and fine-tuned by different cytokines strongly depending on the time when the cytokines are released and their concentration. The present results will help to understand the pericyte mediated defense mechanisms in the brain.}, language = {en} } @article{DuyduBasaranYalcinetal.2019, author = {Duydu, Yalcin and Basaran, Nursen and Yalcin, Can {\"O}zg{\"u}r and Ustundag, Aylin and Aydin, Sevtap and Anlar, Hatice Gul and Bacanli, Merve and Aydos, Kaan and Atabekoglu, Cem Somer and Golka, Klaus and Ickstadt, Katja and Schwerdtle, Tanja and Werner, Matthias and Bolt, Hermann M.}, title = {Boron-exposed male workers in Turkey}, series = {Archives of toxicology : official journal of EUROTOX}, volume = {93}, journal = {Archives of toxicology : official journal of EUROTOX}, number = {3}, publisher = {Springer}, address = {Heidelberg}, issn = {0340-5761}, doi = {10.1007/s00204-019-02391-z}, pages = {743 -- 751}, year = {2019}, abstract = {Boron-associated shifts in sex ratios at birth were suggested earlier and attributed to a decrease in Y- vs. X-bearing sperm cells. As the matter is pivotal in the discussion of reproductive toxicity of boron/borates, re-investigation in a highly borate-exposed population was required. In the present study, 304 male workers in Bandirma and Bigadic (Turkey) with different degrees of occupational and environmental exposure to boron were investigated. Boron was quantified in blood, urine and semen, and the persons were allocated to exposure groups along B blood levels. In the highest ("extreme") exposure group (n = 69), calculated mean daily boron exposures, semen boron and blood boron concentrations were 44.91 +/- 18.32 mg B/day, 1643.23 +/- 965.44 ng B/g semen and 553.83 +/- 149.52 ng B/g blood, respectively. Overall, an association between boron exposure and Y:X sperm ratios in semen was not statistically significant (p > 0.05). Also, the mean Y:X sperm ratios in semen samples of workers allocated to the different exposure groups were statistically not different in pairwise comparisons (p > 0.05). Additionally, a boron-associated shift in sex ratio at birth towards female offspring was not visible. In essence, the present results do not support an association between boron exposure and decreased Y:X sperm ratio in males, even under extreme boron exposure conditions.}, language = {en} } @article{DuyduBasaranUstundagetal.2018, author = {Duydu, Yalcin and Basaran, Nursen and Ustundag, Aylin and Aydin, Sevtap and Yalcin, Can Ozgur and Anlar, Hatice Gul and Bacanli, Merve and Aydos, Kaan and Atabekoglu, Cem Somer and Golka, Klaus and Ickstadt, Katja and Schwerdtle, Tanja and Werner, Matthias and Meyer, S{\"o}ren and Bolt, Hermann M.}, title = {Birth weights of newborns and pregnancy outcomes of environmentally boron-exposed females in Turkey}, series = {Archives of toxicology : official journal of EUROTOX}, volume = {92}, journal = {Archives of toxicology : official journal of EUROTOX}, number = {8}, publisher = {Springer}, address = {Heidelberg}, issn = {0340-5761}, doi = {10.1007/s00204-018-2238-4}, pages = {2475 -- 2485}, year = {2018}, abstract = {Boric acid and sodium borates are currently classified as being toxic to reproduction under "Category 1B" with the hazard statement of "H360 FD" in the European CLP regulation. This has prompted studies on boron-mediated reprotoxic effects in male workers in boron mining areas and boric acid production plants. By contrast, studies on boron-mediated developmental effects in females are scarce. The present study was designed to fill this gap. Hundred and ninety nine females residing in Bandirma and Bigadic participated in this study investigating pregnancy outcomes. The participants constituted a study group covering blood boron from low (< 100 ng B/g blood, n = 143) to high (> 150 ng B/g blood, n = 27) concentrations. The mean blood boron concentration and the mean estimated daily boron exposure of the high exposure group was 274.58 (151.81-975.66) ng B/g blood and 24.67 (10.47-57.86) mg B/day, respectively. In spite of the high level of daily boron exposure, boron-mediated adverse effects on induced abortion, spontaneous abortion (miscarriage), stillbirth, infant death, neonatal death, early neonatal death, preterm birth, congenital anomalies, sex ratio and birth weight of newborns were not observed.}, language = {en} } @article{TurriniKroepflJensenetal.2018, author = {Turrini, Nikolaus G. and Kroepfl, Nina and Jensen, Kenneth Bendix and Reiter, Tamara C. and Francesconi, Kevin A. and Schwerdtle, Tanja and Kroutil, Wolfgang and Kuehnelt, Doris}, title = {Biosynthesis and isolation of selenoneine from genetically modified fission yeast}, series = {Metallomics : integrated biometal science}, volume = {10}, journal = {Metallomics : integrated biometal science}, number = {10}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1756-5901}, doi = {10.1039/c8mt00200b}, pages = {1532 -- 1538}, year = {2018}, abstract = {Selenoneine, a naturally occurring form of selenium, is the selenium analogue of ergothioneine, a sulfur species with health relevance not only as a purported antioxidant but likely also beyond. Selenoneine has been speculated to exhibit similar effects. To study selenoneine's health properties as well as its metabolic transformation, the pure compound is required. Chemical synthesis of selenoneine, however, is challenging and biosynthetic approaches have been sought. We herein report the biosynthesis and isolation of selenoneine from genetically modified fission yeast Schizosaccharomyces pombe grown in a medium containing sodium selenate. After cell lysis and extraction with methanol, selenoneine was purified by three consecutive preparative reversed-phase HPLC steps. The product obtained at the mg level was characterised by high resolution mass spectrometry, NMR and HPLC/ICPMS. Biosynthesis was found to be a promising alternative to chemical synthesis, and should be suitable for upscaling to produce higher amounts of this important selenium species in the future.}, language = {en} } @article{WittEbertMeyeretal.2017, author = {Witt, Barbara and Ebert, Franziska and Meyer, S{\"o}ren and Francesconi, Kevin A. and Schwerdtle, Tanja}, title = {Assessing neurodevelopmental effects of arsenolipids in pre-differentiated human neurons}, series = {Molecular nutrition \& food research : bioactivity, chemistry, immunology, microbiology, safety, technology}, volume = {61}, journal = {Molecular nutrition \& food research : bioactivity, chemistry, immunology, microbiology, safety, technology}, publisher = {Wiley}, address = {Hoboken}, issn = {1613-4125}, doi = {10.1002/mnfr.201700199}, pages = {10}, year = {2017}, abstract = {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.}, language = {en} } @article{WittBornhorstMitzeetal.2017, author = {Witt, B. and Bornhorst, Julia and Mitze, H. and Ebert, Franziska and Meyer, S. and Francesconi, Kevin A. and Schwerdtle, Tanja}, title = {Arsenolipids exert less toxicity in a human neuron astrocyte co-culture as compared to the respective monocultures}, series = {Metallomics : integrated biometal science}, volume = {9}, journal = {Metallomics : integrated biometal science}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1756-5901}, doi = {10.1039/c7mt00036g}, pages = {442 -- 446}, year = {2017}, abstract = {Arsenic-containing hydrocarbons (AsHCs), natural products found in seafood, have recently been shown to exert toxic effects in human neurons. In this study we assessed the toxicity of three AsHCs in cultured human astrocytes. Due to the high cellular accessibility and substantial toxicity observed astrocytes were identified as further potential brain target cells for arsenolipids. Thereby, the AsHCs exerted a 5-19-fold higher cytotoxicity in astrocytes as compared to arsenite. Next we compared the toxicity of the arsenicals in a co-culture model of the respective human astrocytes and neurons. Notably the AsHCs did not show any substantial toxic effects in the co-culture, while arsenite did. The arsenic accessibility studies indicated that in the co-culture astrocytes protect neurons against cellular arsenic accumulation especially after incubation with arsenolipids. In summary, these data underline the importance of the glial-neuron interaction when assessing the in vitro neurotoxicity of new unclassified metal species.}, language = {en} }