TY - GEN A1 - Maares, Maria A1 - Keil, Claudia A1 - Koza, Jenny A1 - Straubing, Sophia A1 - Schwerdtle, Tanja A1 - Haase, Hajo T1 - In Vitro Studies on Zinc Binding and Buffering by Intestinal Mucins T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The investigation of luminal factors influencing zinc availability and accessibility in the intestine is of great interest when analyzing parameters regulating intestinal zinc resorption. Of note, intestinal mucins were suggested to play a beneficial role in the luminal availability of zinc. Their exact zinc binding properties, however, remain unknown and the impact of these glycoproteins on human intestinal zinc resorption has not been investigated in detail. Thus, the aim of this study is to elucidate the impact of intestinal mucins on luminal uptake of zinc into enterocytes and its transfer into the blood. In the present study, in vitro zinc binding properties of mucins were analyzed using commercially available porcine mucins and secreted mucins of the goblet cell line HT-29-MTX. The molecular zinc binding capacity and average zinc binding affinity of these glycoproteins demonstrates that mucins contain multiple zinc-binding sites with biologically relevant affinity within one mucin molecule. Zinc uptake into the enterocyte cell line Caco-2 was impaired by zinc-depleted mucins. Yet this does not represent their form in the intestinal lumen in vivo under zinc adequate conditions. In fact, zinc-uptake studies into enterocytes in the presence of mucins with differing degree of zinc saturation revealed zinc buffering by these glycoproteins, indicating that mucin-bound zinc is still available for the cells. Finally, the impact of mucins on zinc resorption using three-dimensional cultures was studied comparing the zinc transfer of a Caco-2/HT-29-MTX co-culture and conventional Caco-2 monoculture. Here, the mucin secreting co-cultures yielded higher fractional zinc resorption and elevated zinc transport rates, suggesting that intestinal mucins facilitate the zinc uptake into enterocytes and act as a zinc delivery system for the intestinal epithelium. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1079 KW - intestinal zinc resorption KW - zinc binding KW - mucus layer KW - intestinal mucins KW - in vitro intestinal model KW - goblet cells KW - Caco-2/HT-29-MTX-model Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469078 SN - 1866-8372 IS - 1079 ER - TY - GEN A1 - Alker, Wiebke A1 - Schwerdtle, Tanja A1 - Schomburg, Lutz A1 - Haase, Hajo T1 - A Zinpyr-1-based fluorimetric microassay for free zinc in human serum T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Zinc is an essential trace element, making it crucial to have a reliable biomarker for evaluating an individual’s zinc status. The total serum zinc concentration, which is presently the most commonly used biomarker, is not ideal for this purpose, but a superior alternative is still missing. The free zinc concentration, which describes the fraction of zinc that is only loosely bound and easily exchangeable, has been proposed for this purpose, as it reflects the highly bioavailable part of serum zinc. This report presents a fluorescence-based method for determining the free zinc concentration in human serum samples, using the fluorescent probe Zinpyr-1. The assay has been applied on 154 commercially obtained human serum samples. Measured free zinc concentrations ranged from 0.09 to 0.42 nM with a mean of 0.22 ± 0.05 nM. It did not correlate with age or the total serum concentrations of zinc, manganese, iron or selenium. A negative correlation between the concentration of free zinc and total copper has been seen for sera from females. In addition, the free zinc concentration in sera from females (0.21 ± 0.05 nM) was significantly lower than in males (0.23 ± 0.06 nM). The assay uses a sample volume of less than 10 µL, is rapid and cost-effective and allows us to address questions regarding factors influencing the free serum zinc concentration, its connection with the body’s zinc status, and its suitability as a future biomarker for an individual’s zinc status. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1086 KW - zinc KW - free zinc KW - serum KW - biomarker KW - fluorescent probe KW - Zinypr-1 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472833 SN - 1866-8372 IS - 1086 ER - TY - GEN A1 - Mayer, Lena S. A1 - Uciechowski, Peter A1 - Meyer, Sören A1 - Schwerdtle, Tanja A1 - Rink, Lothar A1 - Haase, Hajo T1 - Differential impact of zinc deficiency on phagocytosis, oxidative burst, and production of pro-inflammatory cytokines by human monocytes N2 - Zinc deficiency has a fundamental influence on the immune defense, with multiple effects on different immune cells, resulting in a major impairment of human health. Monocytes and macrophages are among the immune cells that are most fundamentally affected by zinc, but the impact of zinc on these cells is still far from being completely understood. Therefore, this study investigates the influence of zinc deficiency on monocytes of healthy human donors. Peripheral blood mononuclear cells, which include monocytes, were cultured under zinc deficient conditions for 3 days. This was achieved by two different methods: by application of the membrane permeable chelator N,N,N0´,N0´-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) or by removal of zinc from the culture medium using a CHELEX 100 resin. Subsequently, monocyte functions were analyzed in response to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Zinc depletion had differential effects. On the one hand, elimination of bacterial pathogens by phagocytosis and oxidative burst was elevated. On the other hand, the production of the inflammatory cytokines tumor necrosis factor (TNF)-a and interleukin (IL)-6 was reduced. This suggests that monocytes shift from intercellular communication to basic innate defensive functions in response to zinc deficiency. These results were obtained regardless of the method by which zinc deficiency was achieved. However, CHELEX-treated medium strongly augmented cytokine production, independently from its capability for zinc removal. This side-effect severely limits the use of CHELEX for investigating the effects of zinc deficiency on innate immunity. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 281 Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-99405 ER - TY - GEN A1 - Baesler, Jessica A1 - Michaelis, Vivien A1 - Stiboller, Michael A1 - Haase, Hajo A1 - Aschner, Michael A1 - Schwerdtle, Tanja A1 - Sturzenbaum, Stephen R. A1 - Bornhorst, Julia T1 - Nutritive manganese and zinc overdosing in aging c. elegans result in a metallothionein-mediated alteration in metal homeostasis T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Manganese (Mn) and zinc (Zn) are not only essential trace elements, but also potential exogenous risk factors for various diseases. Since the disturbed homeostasis of single metals can result in detrimental health effects, concerns have emerged regarding the consequences of excessive exposures to multiple metals, either via nutritional supplementation or parenteral nutrition. This study focuses on Mn-Zn-interactions in the nematode Caenorhabditis elegans (C. elegans) model, taking into account aspects related to aging and age-dependent neurodegeneration. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1364 KW - aging KW - C. elegans KW - homeostasis KW - manganese KW - zinc Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-514995 SN - 1866-8372 IS - 8 ER -