Gerich, Florian J.

[["dc.bibliographiccitation.firstpage","2590"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","NeuroImage"],["dc.bibliographiccitation.lastpage","2602"],["dc.bibliographiccitation.volume","54"],["dc.contributor.author","Funke, Frank"],["dc.contributor.author","Gerich, Florian J."],["dc.contributor.author","Müller, Michael"],["dc.date.accessioned","2018-09-28T10:30:44Z"],["dc.date.available","2018-09-28T10:30:44Z"],["dc.date.issued","2011"],["dc.description.abstract","The cellular redox status is determined by various extra- and intracellular factors, and contributes to cytosolic signaling and oxidative stress. Especially mitochondria modulate the cytosolic redox status by oxidizing NADH and FADH(2) and generating reactive oxygen species (ROS). Whereas cellular NADH and FAD levels are reliably detectable as autofluorescence, quantifying cellular ROS production is more demanding, because the various redox-sensitive dyes share major disadvantages including irreversible oxidation, autooxidation and photosensitivity. As an alternative, we took advantage of a genetically engineered redox-sensitive green fluorescent protein (roGFP1), carefully evaluated its response properties, and succeeded to monitor ROS dynamics in cultured rat hippocampal neurons and organotypic slices. The ratiometric properties and reversible oxidation/reduction of roGFP1 enable reliable, semi-quantitative analyses of cytosolic ROS levels and redox status. Cytosolically expressed roGFP1 readily responded to hydrogen peroxide, superoxide and hydroxyl radicals, and was only negligibly affected by intracellular pH or Cl(-) content. Furthermore, roGFP1 was well suited for two-photon excitation, reliably detected changes in endogenous ROS production during impaired mitochondrial respiration or neuronal stimulation, and was even capable of visualizing perimitochondrial ROS microdomains. Modulation of cellular scavenging systems confirmed the functional integration of roGFP1 into the cellular ROS and redox balance. We conclude that roGFP1 is well suited for dynamic, compartment specific, subcellular analyses even in complex neuronal networks. The ability to correlate dynamic changes in cellular ROS levels with mitochondrial metabolism and neuronal network activity is a promising step towards a detailed mechanistic understanding of redox- and ROS-mediated signaling in normal and diseased brain function."],["dc.identifier.doi","10.1016/j.neuroimage.2010.11.031"],["dc.identifier.pmid","21081169"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/6124"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/15859"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.relation.eissn","1095-9572"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Dynamic, semi-quantitative imaging of intracellular ROS levels and redox status in rat hippocampal neurons"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","937"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Pflügers Archiv : European Journal of Physiology"],["dc.bibliographiccitation.lastpage","952"],["dc.bibliographiccitation.volume","458"],["dc.contributor.author","Gerich, Florian J."],["dc.contributor.author","Funke, Frank"],["dc.contributor.author","Hildebrandt, Belinda"],["dc.contributor.author","Fasshauer, Martin"],["dc.contributor.author","Müller, Michael"],["dc.date.accessioned","2018-09-28T10:04:34Z"],["dc.date.available","2018-09-28T10:04:34Z"],["dc.date.issued","2009"],["dc.description.abstract","Reactive oxygen species (ROS) released from (dys-)functioning mitochondria contribute to normal and pathophysiological cellular signaling by modulating cytosolic redox state and redox-sensitive proteins. To identify putative redox targets involved in such signaling, we exposed hippocampal neurons to hydrogen peroxide (H(2)O(2)). Redox-sensitive dyes indicated that externally applied H(2)O(2) may oxidize intracellular targets in cell cultures and acute tissue slices. In cultured neurons, H(2)O(2) (EC(50) 118 microM) induced an intracellular Ca(2+) rise which could still be evoked upon Ca(2+) withdrawal and mitochondrial uncoupling. It was, however, antagonized by thapsigargin, dantrolene, 2-aminoethoxydiphenyl borate, and high levels of ryanodine, which identifies the endoplasmic reticulum (ER) as the intracellular Ca(2+) store involved. Intracellular accumulation of endogenously generated H(2)O(2)-provoked by inhibiting glutathione peroxidase-also released Ca(2+) from the ER, as did extracellular generation of superoxide. Phospholipase C (PLC)-mediated metabotropic signaling was depressed in the presence of H(2)O(2), but cytosolic cyclic adenosine-5'-monophosphate (cAMP) levels were not affected. H(2)O(2) (0.2-5 mM) moderately depolarized mitochondria, halted their intracellular trafficking in a Ca(2+)- and cAMP-independent manner, and directly oxidized cellular nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH(2)). In part, the mitochondrial depolarization reflects uptake of Ca(2+) previously released from the ER. We conclude that H(2)O(2) releases Ca(2+) from the ER via both ryanodine and inositol trisphosphate receptors. Mitochondrial function is not markedly impaired even by millimolar concentrations of H(2)O(2). Such modulation of Ca(2+) signaling and organelle interaction by ROS affects the efficacy of PLC-mediated metabotropic signaling and may contribute to the adjustment of neuronal function to redox conditions and metabolic supply."],["dc.identifier.doi","10.1007/s00424-009-0672-0"],["dc.identifier.pmid","19430810"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/15851"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.eissn","1432-2013"],["dc.title","H(2)O(2)-mediated modulation of cytosolic signaling and organelle function in rat hippocampus"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]