Ivo florin Scheiber
Research skills
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TechnicalPrimary Cell Culture, Cell Culture Techniques
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ITMS - office, Adobe Photoshop, Sigma Plot
Research interests
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InterestsCopper, Astrocyte, Glia, Neurobiochemistry, Neurodegeneration, AAS, Glycolysis, Glutathione
Other
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LanguagesGerman, English
Publications
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3.54Impact points
Copper export from cultured astrocytes.
Neurochemistry international. 02/2012; 60(3):292-300.
Copper is an essential trace metal that is required as a catalytic co-factor or a structural component of several important enzymes. However, since excess of copper can also harm cells due to its potential to catalyse the generation of toxic reactive oxygen species, transport of copper and the cellu... [more] Copper is an essential trace metal that is required as a catalytic co-factor or a structural component of several important enzymes. However, since excess of copper can also harm cells due to its potential to catalyse the generation of toxic reactive oxygen species, transport of copper and the cellular copper content are tightly regulated. Astrocytes are known to efficiently take up copper ions, but it was not known whether these cells are also able to export copper. Treatment of astrocyte-rich primary cultures for 24h with copper chloride caused a concentration-dependent increase in the specific cellular copper content. During further 24h incubation in the absence of copper chloride, the copper-loaded astrocytes remained viable and released up to 45% of the accumulated copper. The rate of copper export was proportional to the amount of cellular copper, was almost completely prevented by lowering the incubation temperature to 4°C and was partly prevented by the endocytosis inhibitor amiloride. Copper export is most likely mediated by the copper ATPase ATP7A, since this transporter is expressed in astrocyte cultures and its cellular location is strongly affected by the absence or the presence of extracellular copper. The potential of cultured astrocytes to export copper suggests that astrocytes provide neighbouring cells in brain with this essential trace element.
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1.93Impact points
Copper-treatment increases the cellular GSH content and accelerates GSH export from cultured rat astrocytes.
Neuroscience letters. 07/2011; 498(1):42-6.
To test whether copper exposure affects astroglial glutathione (GSH) metabolism, we have exposed astrocyte-rich primary cultures with copper chloride in concentrations of up to 30 μM and investigated cellular and extracellular GSH contents. Cultured astrocytes accumulated copper in a concentration-d... [more] To test whether copper exposure affects astroglial glutathione (GSH) metabolism, we have exposed astrocyte-rich primary cultures with copper chloride in concentrations of up to 30 μM and investigated cellular and extracellular GSH contents. Cultured astrocytes accumulated copper in a concentration-dependent manner thereby increasing the specific cellular copper content within 24h up to sevenfold. The increase in the cellular copper content was accompanied by a proportional increase in the specific cellular GSH content that reached up to 165% of the values of cells that had been incubated without copper, while the low cellular content of GSH disulfide (GSSG) remained unaltered in copper-treated cells. Also the rate of GSH export was significantly increased after copper exposure reaching up to 177% of control values. The export of GSH from control and copper-treated astrocytes was lowered by more than 70%, if cells were incubated in presence of the multidrug-resistance protein (Mrp) 1 inhibitor MK571 or at a low incubation temperature of 4°C. These data demonstrate that copper accumulation stimulates GSH synthesis and accelerates Mrp1-mediated GSH export from cultured astrocytes. These processes are likely to contribute to the resistance of astrocytes against copper toxicity and could improve the supply of GSH precursors from astrocytes to neurons.
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2.72Impact points
Copper accelerates glycolytic flux in cultured astrocytes.
Neurochemical research. 02/2011; 36(5):894-903.
Astrocyte-rich primary cultures were used to investigate the consequences of a copper exposure on the glucose metabolism of astrocytes. After application of CuCl(2) (30 μM) the specific cellular copper content increased from initial 1.5 ± 0.2 nmol/mg to a steady state level of 7.9 ± 0.9 nmol/mg with... [more] Astrocyte-rich primary cultures were used to investigate the consequences of a copper exposure on the glucose metabolism of astrocytes. After application of CuCl(2) (30 μM) the specific cellular copper content increased from initial 1.5 ± 0.2 nmol/mg to a steady state level of 7.9 ± 0.9 nmol/mg within about 12 h. The copper accumulation was accompanied by a significant increase in the extracellular lactate concentration. The stimulating effect of copper on the lactate production remained after removal of extracellular copper. Copper treatment accelerated the rates of both glucose consumption and lactate production by about 60%. The copper induced acceleration of glycolytic flux was prevented by inhibition of protein synthesis, and additive to the stimulation of glycolysis observed for inhibitors of respiration or prolyl hydroxylases. A copper induced stimulation of glycolytic flux in astrocytes could have severe consequences for the glucose metabolism of the brain in conditions of copper overload.
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3.54Impact points
Zinc prevents the copper-induced damage of cultured astrocytes.
Neurochemistry international. 10/2010; 57(3):314-22.
Copper is essential for several cellular processes, but an excess of cellular copper is known to be cell toxic. To study the consequences of a copper treatment of astrocytes, we have used astrocyte-rich primary cultures as model system to investigate cellular functions and cellular integrity of thes... [more] Copper is essential for several cellular processes, but an excess of cellular copper is known to be cell toxic. To study the consequences of a copper treatment of astrocytes, we have used astrocyte-rich primary cultures as model system to investigate cellular functions and cellular integrity of these cells after application of micromolar concentrations of copper chloride. After exposure of the cells to copper, the cell-associated copper content increased strongly in a time and concentration dependent manner. While incubation of cultured astrocytes with 3 microM copper hardly affected the cells during incubation for up to 4h, presence of 10 microM or 30 microM copper severly compromised cellular functions as demonstrated by a loss in total and soluble protein contents, a lowered MTT reduction capacity, lowered activities of the enzymes lactate dehydrogenase, glucose-6-phosphate dehydrogenase and glutathione reductase, a lowered cellular glutathione content, an increased lipid peroxidation, and an elevated membrane permeability for propidium iodide. Presence of an excess of zinc inhibited cellular copper accumulation and prevented most of the detrimental consequences of a copper exposure, suggesting that the beneficial effect of zinc against the copper-induced impairment of cultured astrocytes is mediated by inhibition of the cellular copper accumulation.
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2.26Impact points
Synergistic accumulation of iron and zinc by cultured astrocytes.
Journal of neural transmission (Vienna, Austria : 1996). 07/2010; 117(7):809-17.
Iron and zinc are essential for normal brain function, yet the mechanisms used by astrocytes to scavenge non-transferrin-bound iron (NTBI) and zinc are not well understood. Ischaemic stroke, traumatic brain injury and Alzheimer's disease are associated with perturbations in the metabolism of NTB... [more] Iron and zinc are essential for normal brain function, yet the mechanisms used by astrocytes to scavenge non-transferrin-bound iron (NTBI) and zinc are not well understood. Ischaemic stroke, traumatic brain injury and Alzheimer's disease are associated with perturbations in the metabolism of NTBI and zinc, suggesting that these two metals may collectively contribute to pathology. The present study has investigated the accumulation of NTBI and zinc by rat primary astrocyte cultures. It was found that astrocytes express mRNA for both divalent metal transporter 1 (DMT1) and Zip14, indicating the potential for these transporters to contribute to the accumulation of NTBI and zinc by these cells. Astrocytes were found to accumulate iron from ferric chloride in a time- and dose-dependent manner, and the rate of accumulation was strongly stimulated by co-incubation with zinc acetate. In addition, cultured astrocytes rapidly accumulated zinc from zinc acetate, and this accumulation was stimulated by co-incubation with ferric chloride. Because a synergistic stimulation of iron and zinc accumulation is inconsistent with the known properties of DMT1 and Zip14, the present results suggest that additional mechanisms assist astrocytes to scavenge iron and zinc when they are present together in the extracellular compartment. These mechanisms may be involved in disorders that involve elevations in the extracellular concentrations of these metal ions.
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3.54Impact points
Copper accumulation by cultured astrocytes.
Neurochemistry international. 12/2009;
To study copper transport in brain astrocytes, we have used astrocyte-rich primary cultures as model system. Cells in these cultures contained a basal copper content of 1.1+/-0.4nmol per mg protein. The cellular copper content increased strongly after application of copper chloride in a time and con... [more] To study copper transport in brain astrocytes, we have used astrocyte-rich primary cultures as model system. Cells in these cultures contained a basal copper content of 1.1+/-0.4nmol per mg protein. The cellular copper content increased strongly after application of copper chloride in a time and concentration-dependent manner. Analysis of the linear copper accumulation during the first 5min of copper exposure revealed that cultured astrocytes accumulated copper with saturable kinetics with apparent K(M)- and V(max)-values of 9.4+/-1.8muM and 0.76+/-0.13nmol/(minxmg protein), respectively. In contrast, incubation of astrocytes with copper in the presence of ascorbate caused a linear increase of the copper accumulation rates for copper concentrations of up to 30muM. In addition, copper accumulation was strongly inhibited by the presence of an excess of zinc or of various other divalent metal ions. The presence of mRNA and of immunoreactivity of the copper transport protein Ctr1 in astrocyte cultures suggests that Ctr1 contributes to the observed copper accumulation. However, since some characteristics of the observed copper accumulation are not consistent with Ctr1-mediated copper transport, additional Ctr1-independent mechanism(s) are likely to be involved in astrocytic copper accumulation.
