0000000000147971

AUTHOR

Katrin Dersch

showing 5 related works from this author

Hypersusceptibility of neutrophil granulocytes towards lethal action of free fatty acids contained in enzyme-modified atherogenic low density lipopro…

2008

Abstract Objective The bulk of LDL entrapped in the arterial intima is modified by hydrolytic enzymes, leading to extensive cleavage of cholesterylesters and liberation of fatty acids. The latter induce apoptosis in endothelial cells but are far less cytotoxic towards macrophages. We have compared the cytotoxic effects of enzymatically modified LDL (E-LDL) on macrophages and polymorphonuclear granulocytes (PMN). Methods and results E-LDL displayed toxicity towards PMN at far lower concentrations than towards monocyte-derived macrophages. Native or oxidized LDL had no effect. Free fatty acids contained in E-LDL were the cause of the observed toxicity, which could be mimicked by linoleic acid…

Cell Membrane PermeabilityTime FactorsCell SurvivalNeutrophilsLinoleic acidGranulocyteFatty Acids NonesterifiedHemolysisLinoleic Acidchemistry.chemical_compoundAdenosine TriphosphateSuperoxidesmedicineAnimalsHumansPropidium iodideCells CulturedPeroxidaseRespiratory BurstArachidonic AcidCell DeathL-Lactate DehydrogenaseSuperoxideHydrolysisMacrophagesSterol EsteraseAtherosclerosisRespiratory burstLipoproteins LDLOleic acidmedicine.anatomical_structurechemistryBiochemistryLow-density lipoproteinlipids (amino acids peptides and proteins)Arachidonic acidCalciumRabbitsCardiology and Cardiovascular MedicineOleic AcidPeptide HydrolasesAtherosclerosis
researchProduct

Pore-forming Staphylococcus aureus alpha-toxin triggers epidermal growth factor receptor-dependent proliferation.

2006

Staphylococcal alpha-toxin is an archetypal killer protein that homo-oligomerizes in target cells to create small transmembrane pores. The membrane-perforating beta-barrel motif is a conserved attack element of cytolysins of Gram-positive and Gram-negative bacteria. Following the recognition that nucleated cells can survive membrane permeabilization, a profile of abundant transcripts was obtained in transiently perforated keratinocytes. Several immediate early genes were found to be upregulated, reminiscent of the cellular response to growth factors. Cell cycle analyses revealed doubling of S + G2/M phase cells 26 h post toxin treatment. Determination of cell counts uncovered that after an …

KeratinocytesStaphylococcus aureusSrc Homology 2 Domain-Containing Transforming Protein 1ImmunologyCellBacterial ToxinsBlotting WesternFluorescent Antibody TechniqueTransfectionMicrobiologyCell LineHemolysin ProteinsDownregulation and upregulationNucleated cellVirologymedicineHumansGrowth factor receptor inhibitorEpidermal growth factor receptorStaphylococcus aureus alpha toxinAdaptor Proteins Signal TransducingCell Line TransformedCell ProliferationbiologyCytotoxinsReverse Transcriptase Polymerase Chain ReactionGene Expression ProfilingCell CycleCell cycleFlow CytometryTransmembrane proteinCell biologyErbB Receptorsmedicine.anatomical_structureShc Signaling Adaptor Proteinsbiology.proteinMitogensSignal TransductionCellular microbiology
researchProduct

Differential role of p38 mitogen activated protein kinase for cellular recovery from attack by pore-forming S. aureus alpha-toxin or streptolysin O.

2006

Following the observation that cells are able to recover from membrane lesions incurred by Staphylococcus aureus alpha-toxin and streptolysin O (SLO), we investigated the role of p38 in this process. p38 phosphorylation occurred in response to attack by both toxins, commencing within minutes after toxin treatment and waning after several hours. While SLO reportedly activates p38 via ASK1 and ROS, we show that this pathway does not play a major role for p38 induction in alpha-toxin-treated cells. Strikingly divergent effects of p38 blockade were noted depending on the toxin employed. In the case of alpha-toxin, inhibition of p38 within the time frame of its activation led to disruption of th…

KeratinocytesProgrammed cell deathStaphylococcus aureusCell Membrane Permeabilityp38 mitogen-activated protein kinasesBacterial ToxinsBiophysicsBiologymedicine.disease_causeMAP Kinase Kinase Kinase 5Biochemistryp38 Mitogen-Activated Protein KinasesMicrobiologyHemolysin ProteinsAdenosine TriphosphateBacterial ProteinsProto-Oncogene ProteinsmedicineHumansASK1PhosphorylationMolecular BiologyCells CulturedPore-forming toxinToxinCell MembraneCell BiologyProtein-Tyrosine KinasesBlockadeCell biologyEnzyme ActivationStreptolysinsPhosphorylationStreptolysinBiochemical and biophysical research communications
researchProduct

Fatty acids liberated from low-density lipoprotein trigger endothelial apoptosis via mitogen-activated protein kinases.

2005

Enzymatic modification of low-density lipoprotein (LDL) as it probably occurs in the arterial intima drastically increases its cytotoxicity, which could be relevant for the progression of atherosclerotic lesions. LDL was treated with a protease and cholesterylesterase to generate a derivative similar to lesional LDL, with a high content of free cholesterol and fatty acids. Exposure of endothelial cells to the enzymatically modified lipoprotein (E-LDL), but not to native or oxidized LDL, resulted in programmed cell death. Apoptosis was triggered by apoptosis signal-regulating kinase 1 dependent phosphorylation of p38. Depletion and reconstitution experiments identified free fatty acids (FFA)…

Programmed cell deathp38 mitogen-activated protein kinasesBlotting WesternApoptosisDNA FragmentationBiologyFatty Acids NonesterifiedMAP Kinase Kinase Kinase 5p38 Mitogen-Activated Protein Kinaseschemistry.chemical_compoundHumansPhosphorylationMolecular BiologyCells CulturedCaspase 7Cell growthKinaseCaspase 3Cell BiologyCell biologyLipoproteins LDLchemistryBiochemistryApoptosisLow-density lipoproteinCaspasesPhosphorylationlipids (amino acids peptides and proteins)Endothelium VascularLipoproteinOleic AcidCell death and differentiation
researchProduct

Enzymatically hydrolyzed low-density lipoprotein modulates inflammatory responses in endothelial cells

2009

SummaryThere is evidence that low-density lipoprotein (LDL) is modified by hydrolytic enzymes,and that the product (E-LDL) induces selective production of interleukin 8 (IL-8) in endothelial cells. Since nuclear factor-kappaB (NF-κB) is a major regulator of IL-8 transcription, we studied its activation in endothelial cells treated with E-LDL. Unexpectedly,the modified lipoprotein not only failed to activate NF-κB, but completely blocked its activation by tumour necrosis factor-alpha (TNF-α) in EA.hy926-cells, as assessed by electrophoretic mobility shift assays and immunofluorescence. Inhibition occurred upstream of NF-κB translocation, as inhibitor of NF-κB- (IκB)-phosphorylation was suppr…

Time FactorsProto-Oncogene Proteins c-junPyridinesmedicine.medical_treatmentFatty Acids NonesterifiedBiologyp38 Mitogen-Activated Protein KinasesCell Linechemistry.chemical_compoundNF-KappaB Inhibitor alphamedicineHumansTrypsinInterleukin 8PhosphorylationPromoter Regions GeneticProtein Kinase InhibitorsTranscription factorInflammationTumor Necrosis Factor-alphaActivator (genetics)HydrolysisInterleukin-8ImidazolesTranscription Factor RelAEndothelial CellsNF-κBHematologySterol EsteraseMolecular biologyLipoproteins LDLTranscription Factor AP-1Endothelial stem cellCytokineBiochemistrychemistryLow-density lipoproteinI-kappa B ProteinsLipoproteinThrombosis and Haemostasis
researchProduct