TY - JOUR A1 - Henze, Andrea A1 - Homann, Thomas A1 - Rohn, Isabelle A1 - Aschner, Michael A. A1 - Link, Christopher D. A1 - Kleuser, Burkhard A1 - Schweigert, Florian J. A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin JF - Scientific reports N2 - 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. KW - n-acetyl-cysteine KW - s-glutathionylation KW - force-field KW - c. elegans KW - life-span KW - protein KW - cells KW - menadione KW - disease KW - binding Y1 - 2016 U6 - https://doi.org/10.1038/srep37346 SN - 2045-2322 VL - 6 PB - Nature Publishing Group CY - London ER - TY - GEN A1 - Henze, Andrea A1 - Homann, Thomas A1 - Rohn, Isabelle A1 - Aschner, Michael A. A1 - Link, Christopher D. A1 - Kleuser, Burkhard A1 - Schweigert, Florian J. A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 312 KW - binding KW - c. elegans KW - cells KW - disease KW - force-field KW - life-span KW - menadione KW - n-acetyl-cysteine KW - protein KW - s-glutathionylation Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-103674 ER - TY - JOUR A1 - Henze, Andrea A1 - Homann, Thomas A1 - Rohn, Isabelle A1 - Aschner, Michael A. A1 - Link, Christopher D. A1 - Kleuser, Burkhard A1 - Schweigert, Florian J. A1 - Schwerdtle, Tanja A1 - Bornhorst, Julia T1 - Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin JF - Scientific reports N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1038/srep37346 SN - 2045-2322 VL - 6 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Marschall, Talke Anu A1 - Bornhorst, Julia A1 - Kuehnelt, Doris A1 - Schwerdtle, Tanja T1 - Differing cytotoxicity and bioavailability of selenite, methylselenocysteine, selenomethionine, selenosugar 1 and trimethylselenonium ion and their underlying metabolic transformations in human cells JF - Applied computing review : the publication of the ACM Special Interest Group on Applied Computing N2 - Scope: The trace element selenium (Se) is an integral component of our diet. However, its metabolism and toxicity following elevated uptake are not fully understood. Since the either adverse or beneficial health effects strongly depend on the ingested Se species, five low molecular weight species were investigated regarding their toxicological effects, cellular bioavailability and species-specific metabolism in human cells. Methods and results: For the first time, the urinary metabolites methyl-2-acetamido-2-deoxy1- seleno-beta-D-galactopyranoside (selenosugar 1) and trimethylselenonium ion (TMSe) were toxicologically characterised in comparison to the food relevant species methylselenocysteine (MeSeCys), selenomethionine (SeMet) and selenite in human urothelial, astrocytoma and hepatoma cells. In all cell lines selenosugar 1 and TMSe showed no cytotoxicity. Selenite, MeSeCys and SeMet exerted substantial cytotoxicity, which was strongest in the urothelial cells. There was no correlation between the potencies of the respective toxic effects and the measured cellular Se concentrations. Se speciation indicated that metabolism of the respective species is likely to affect cellular toxicity. Conclusion: Despite being taken up, selenosugar 1 and TMSe are non-cytotoxic to urothelial cells, most likely because they are not metabolically activated. The absent cytotoxicity of selenosugar 1 and TMSe up to supra-physiological concentrations, support their importance as metabolites for Se detoxification. KW - Cellular bioavailability KW - ICP-QQQ-MS KW - Selenosugar 1 KW - Small selenium species KW - Speciation Y1 - 2016 U6 - https://doi.org/10.1002/mnfr.201600422 SN - 1613-4125 SN - 1613-4133 VL - 60 SP - 2622 EP - 2632 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Lohren, Hanna A1 - Bornhorst, Julia A1 - Fitkau, Romy A1 - Pohl, Gabriele A1 - Galla, Hans-Joachim A1 - Schwerdtle, Tanja T1 - Effects on and transfer across the blood-brain barrier in vitro-Comparison of organic and inorganic mercury species JF - BMC pharmacology & toxicology N2 - Background: Transport of methylmercury (MeHg) across the blood-brain barrier towards the brain side is well discussed in literature, while ethylmercury (EtHg) and inorganic mercury are not adequately characterized regarding their entry into the brain. Studies investigating a possible efflux out of the brain are not described to our knowledge. Methods: This study compares, for the first time, effects of organic methylmercury chloride (MeHgCl), EtHg-containing thiomersal and inorganic Hg chloride (HgCl2) on as well as their transfer across a primary porcine in vitro model of the blood-brain barrier. Results: With respect to the barrier integrity, the barrier model exhibited a much higher sensitivity towards HgCl2 following basolateral incubation (brain-facing side) as compared to apical application (blood-facing side). These HgCl2 induced effects on the barrier integrity after brain side incubation are comparable to that of the organic species, although MeHgCl and thiomersal exerted much higher cytotoxic effects in the barrier building cells. Hg transfer rates following exposure to organic species in both directions argue for diffusion as transfer mechanism. Inorganic Hg application surprisingly resulted in a Hg transfer out of the brain-facing compartment. Conclusions: In case of MeHgCl and thiomersal incubation, mercury crossed the barrier in both directions, with a slight accumulation in the basolateral, brain-facing compartment, after simultaneous incubation in both compartments. For HgCl2, our data provide first evidence that the blood-brain barrier transfers mercury out of the brain. KW - Organic mercury KW - Inorganic mercury KW - Methylmercury KW - Thiomersal KW - Mercuric mercury KW - In vitro blood-brain barrier model Y1 - 2016 U6 - https://doi.org/10.1186/s40360-016-0106-5 SN - 2050-6511 VL - 17 SP - 422 EP - 433 PB - BioMed Central CY - London ER - TY - GEN A1 - Avila, Daiana Silva A1 - Benedetto, Alexandre A1 - Au, Catherine A1 - Bornhorst, Julia A1 - Aschner, Michael A. T1 - Involvement of heat shock proteins on Mn-induced toxicity in Caenorhabditis elegans T2 - BMC pharmacology and toxicology N2 - Background: All living cells display a rapid molecular response to adverse environmental conditions, and the heat shock protein family reflects one such example. Hence, failing to activate heat shock proteins can impair the cellular response. In the present study, we evaluated whether the loss of different isoforms of heat shock protein ( hsp ) genes in Caenorhabditis elegans would affect their vulnerability to Manganese (Mn) toxicity. Methods: We exposed wild type and selected hsp mutant worms to Mn (30 min) and next evaluated further the most susceptible strains. We analyzed survi val, protein carbonylation (as a marker of oxidative stress) and Parkinson ’ s disease related gene expression immediately after Mn exposure. Lastly, we observed dopaminergic neurons in wild type worms and in hsp-70 mutants following Mn treatment. Analysis of the data was performed by one-way or two way ANOVA, depending on the case, followed by post-hoc Bonferroni test if the overall p value was less than 0.05. Results: We verified that the loss of hsp-70, hsp-3 and chn-1 increased the vulnerability to Mn, as exposed mutant worms showed lower survival rate and increased protein oxidation. The importance of hsp-70 against Mn toxicity was then corroborated in dopaminergic neurons, where Mn neurotoxicity was aggravated. The lack of hsp-70 also blocked the transcriptional upregulation of pink1 , a gene that has been linked to Parkinson ’ sdisease. Conclusions: Taken together, our data suggest that Mn exposu re modulates heat shock protein expression, particularly HSP-70, in C. elegans .Furthermore,lossof hsp-70 increases protein oxidation and dopaminergic neuronal degeneration following manganese exposure, which is associated with the inhibition of pink1 increased expression, thus pot entially exacerbating the v ulnerability to this metal. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 439 KW - Caenorhabitis elegans KW - Manganese KW - heat shock proteins KW - hsp-70 KW - pink1 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407286 ER - TY - JOUR A1 - Avila, Daiana Silva A1 - Benedetto, Alexandre A1 - Au, Catherine A1 - Bornhorst, Julia A1 - Aschner, Michael A. T1 - Involvement of heat shock proteins on Mn-induced toxicity in Caenorhabditis elegans JF - Plant Methods N2 - Background: All living cells display a rapid molecular response to adverse environmental conditions, and the heat shock protein family reflects one such example. Hence, failing to activate heat shock proteins can impair the cellular response. In the present study, we evaluated whether the loss of different isoforms of heat shock protein (hsp) genes in Caenorhabditis elegans would affect their vulnerability to Manganese (Mn) toxicity. Conclusions: Taken together, our data suggest that Mn exposure modulates heat shock protein expression, particularly HSP-70, in C. elegans. Furthermore, loss of hsp-70 increases protein oxidation and dopaminergic neuronal degeneration following manganese exposure, which is associated with the inhibition of pink1 increased expression, thus potentially exacerbating the vulnerability to this metal. KW - Caenorhabitis elegans KW - Manganese KW - Heat shock proteins KW - hsp-70 KW - pink1 Y1 - 2016 U6 - https://doi.org/10.1186/s40360-016-0097-2 SN - 2050-6511 VL - 17 PB - BioMed Central CY - London ER - TY - JOUR A1 - Gubert, Priscila A1 - Puntel, Bruna A1 - Lehmen, Tassia A1 - Bornhorst, Julia A1 - Avila, Daiana Silva A1 - Aschner, Michael A. A1 - Soares, Felix A. A. T1 - Reversible reprotoxic effects of manganese through DAF-16 transcription factor activation and vitellogenin downregulation in Caenorhabditis elegans JF - Life sciences : molecular, cellular and functional basis of therapy N2 - Aims Vitellogenesis is the yolk production process which provides the essential nutrients for the developing embryos. Yolk is a lipoprotein particle that presents lipids and lipid-binding proteins, referred to as vitellogenins (VIT). The Caenorhabditis elegans nematode has six genes encoding VIT lipoproteins. Several pathways are known to regulate vitellogenesis, including the DAF-16 transcription factor. Some reports have shown that heavy metals, such as manganese (Mn), impair brood size in C. elegans; however the mechanisms associated with this effect have yet to be identified. Our aim was to evaluate Mn′s effects on C. elegans reproduction and better understand the pathways related to these effects. Main methods. Young adult larval stage worms were treated for 4 h with Mn in 85 mM NaCl and Escherichia coli OP50 medium. Key findings. Mn reduced egg-production and egg-laying during the first 24 h after the treatment, although the total number of progenies were indistinguishable from the control group levels. This delay may have occurred due to DAF-16 activation, which was noted only after the treatment and was not apparent 24 h later. Moreover, the expression, protein levels and green fluorescent protein (GFP) fluorescence associated with VIT were decreased soon after Mn treatment and recovered after 24 h. Significance Combined, these data suggest that the delay in egg-production is likely regulated by DAF-16 and followed by the inhibition of VIT transport activity. Further studies are needed to clarify the mechanisms associated with Mn-induced DAF-16 activation. KW - Manganese KW - Vitellogenin KW - Caenorhabditis elegans KW - DAF-16 transcription factor KW - Brood size Y1 - 2016 U6 - https://doi.org/10.1016/j.lfs.2016.03.016 SN - 0024-3205 SN - 1879-0631 VL - 151 SP - 218 EP - 223 PB - Elsevier CY - Oxford ER -