@article{KoehlerLutherMeyeretal.2014,
  author    = {K{\"o}hler, Yvonne and Luther, Eva Maria and Meyer, S{\"o}ren and Schwerdtle, Tanja and Dringen, Ralf},
  title     = {Uptake and toxicity of arsenite and arsenate in cultured brain astrocytes},
  series = {Journal of trace elements in medicine and biology},
  volume    = {28},
  journal   = {Journal of trace elements in medicine and biology},
  number    = {3},
  publisher = {Elsevier},
  address   = {Jena},
  issn      = {0946-672X},
  doi       = {10.1016/j.jtemb.2014.04.007},
  pages     = {328 -- 337},
  year      = {2014},
  abstract  = {Inorganic arsenicals are environmental toxins that have been connected with neuropathies and impaired cognitive functions. To investigate whether such substances accumulate in brain astrocytes and affect their viability and glutathione metabolism, we have exposed cultured primary astrocytes to arsenite or arsenate. Both arsenicals compromised the cell viability of astrocytes in a time- and concentration-dependent manner. However, the early onset of cell toxicity in arsenite-treated astrocytes revealed the higher toxic potential of arsenite compared with arsenate. The concentrations of arsenite and arsenate that caused within 24 h half-maximal release of the cytosolic enzyme lactate dehydrogenase were around 0.3 mM and 10 mM, respectively. The cellular arsenic contents of astrocytes increased rapidly upon exposure to arsenite or arsenate and reached after 4 h of incubation almost constant steady state levels. These levels were about 3-times higher in astrocytes that had been exposed to a given concentration of arsenite compared with the respective arsenate condition. Analysis of the intracellular arsenic species revealed that almost exclusively arsenite was present in viable astrocytes that had been exposed to either arsenate or arsenite. The emerging toxicity of arsenite 4 h after exposure was accompanied by a loss in cellular total glutathione and by an increase in the cellular glutathione disulfide content. These data suggest that the high arsenite content of astrocytes that had been exposed to inorganic arsenicals causes an increase in the ratio of glutathione disulfide to glutathione which contributes to the toxic potential of these substances.},
  language  = {en}
}
@article{WehePieperHoltkampetal.2014,
  author    = {Wehe, Christoph A. and Pieper, Imke and Holtkamp, Michael and Thyssen, Georgina M. and Sperling, Michael and Schwerdtle, Tanja and Karst, Uwe},
  title     = {On-line species-unspecific isotope dilution analysis in the picomolar range reveals the time- and species-depending mercury uptake in human astrocytes},
  series = {Analytical \& bioanalytical chemistry},
  volume    = {406},
  journal   = {Analytical \& bioanalytical chemistry},
  number    = {7},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {1618-2642},
  doi       = {10.1007/s00216-013-7608-4},
  pages     = {1909 -- 1916},
  year      = {2014},
  abstract  = {In order to reveal the time-depending mercury species uptake by human astrocytes, a novel approach for total mercury analysis is presented, which uses an accelerated sample introduction system combined on-line with an inductively coupled plasma mass spectrometer equipped with a collision/reaction cell. Human astrocyte samples were incubated with inorganic mercury (HgCl2), methylmercury chloride (MeHgCl), and thimerosal. After 1-h incubation with Hg2+, cellular concentrations of 3 mu M were obtained, whereas for organic species, concentrations of 14-18 mu M could be found. After 24 h, a cellular accumulation factor of 0.3 was observed for the cells incubated with Hg2+, whereas the organic species both showed values of about 5. Due to the obtained steady-state signals, reliable results with relative standard deviations of well below 5 \% and limits of detection in the concentration range of 1 ng L-1 were obtained using external calibration and species-unspecific isotope dilution analysis approaches. The results were further validated using atomic fluorescence spectrometry.},
  language  = {en}
}
@article{WittStibollerRaschkeetal.2021,
  author    = {Witt, Barbara and Stiboller, Michael and Raschke, Stefanie and Friese, Sharleen and Ebert, Franziska and Schwerdtle, Tanja},
  title     = {Characterizing effects of excess copper levels in a human astrocytic cell line with focus on oxidative stress markers},
  series = {Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements, GMS},
  volume    = {65},
  journal   = {Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements, GMS},
  publisher = {Elsevier},
  address   = {M{\"u}nchen},
  issn      = {1878-3252},
  doi       = {10.1016/j.jtemb.2021.126711},
  pages     = {9},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}