@article{PieperWeheBornhorstetal.2014, author = {Pieper, Imke and Wehe, Christoph A. and Bornhorst, Julia and Ebert, Franziska and Leffers, Larissa and Holtkamp, Michael and H{\"o}seler, Pia and Weber, Till and Mangerich, Aswin and B{\"u}rkle, Alexander and Karst, Uwe and Schwerdtle, Tanja}, title = {Mechanisms of Hg species induced toxicity in cultured human astrocytes}, series = {Metallomics}, volume = {2014}, journal = {Metallomics}, number = {6}, issn = {1756-591X}, doi = {10.1039/c3mt00337j}, pages = {662 -- 671}, year = {2014}, abstract = {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.}, language = {en} } @article{MichaelisAengenheisterTuchtenhagenetal.2022, author = {Michaelis, Vivien and Aengenheister, Leonie and Tuchtenhagen, Max and Rinklebe, J{\"o}rg and Ebert, Franziska and Schwerdtle, Tanja and Buerki-Thurnherr, Tina and Bornhorst, Julia}, title = {Differences and interactions in placental manganese and iron transfer across an in vitro model of human villous trophoblasts}, series = {International journal of molecular sciences}, volume = {23}, journal = {International journal of molecular sciences}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms23063296}, pages = {18}, year = {2022}, abstract = {Manganese (Mn) as well as iron (Fe) are essential trace elements (TE) important for the maintenance of physiological functions including fetal development. However, in the case of Mn, evidence suggests that excess levels of intrauterine Mn are associated with adverse pregnancy outcomes. Although Mn is known to cross the placenta, the fundamentals of Mn transfer kinetics and mechanisms are largely unknown. Moreover, exposure to combinations of TEs should be considered in mechanistic transfer studies, in particular for TEs expected to share similar transfer pathways. Here, we performed a mechanistic in vitro study on the placental transfer of Mn across a BeWo b30 trophoblast layer. Our data revealed distinct differences in the placental transfer of Mn and Fe. While placental permeability to Fe showed a clear inverse dose-dependency, Mn transfer was largely independent of the applied doses. Concurrent exposure of Mn and Fe revealed transfer interactions of Fe and Mn, indicating that they share common transfer mechanisms. In general, mRNA and protein expression of discussed transporters like DMT1, TfR, or FPN were only marginally altered in BeWo cells despite the different exposure scenarios highlighting that Mn transfer across the trophoblast layer likely involves a combination of active and passive transport processes.}, language = {en} }