title: N-3 vs. n-6 fatty acids differentially influence calcium signalling and adhesion of inflammatory activated monocytes: impact of lipid rafts.
abstract: BACKGROUND
  Anti-inflammatory n-3 fatty acids (FA) like docosahexaenoic acid (DHA) opposed to the pro-inflammatory n-6 FA arachidonic acid (AA) might modulate lipid rafts within the cell membrane by differential incorporation. In inflammation, monocyte adhesion to endothelial cells is a crucial step mediated by intracellular calcium changes. We investigated whether lipid rafts mediate FA-induced modulation of adhesion and intracellular calcium.
  
  
  METHODS
  In isolated human monocytes and monocytic U937 cells we measured adhesion to human umbilical vein endothelial cells (HUVEC) using a parallel flow chamber and a static assay, adhesion molecules by FACScan, and intracellular calcium by fluorescence. Monocyte lipid rafts were isolated by ultracentrifugation and submitted to gas chromatography for FA analysis.
  
  
  RESULTS
  Pre-incubation with AA or DHA resulted in a predominant incorporation of the respective FA into raft compared to non-raft fraction. DHA as compared to AA significantly reduced monocyte adhesion and calcium release after stimulation with TNF-α while expression of adhesion molecules remained unchanged. Pre-treatment with a calcium chelator abolished the effect of FA on calcium and adhesion. Disruption of lipid rafts prevented FA-induced modulations.
  
  
  CONCLUSIONS
  Incorporation of FA into lipid rafts seem to be crucial for modulation of adhesion under inflammatory conditions.
authors.affiliation: University of Giessen Lung Center (UGLC), University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany.
authors.forename: Martina Barbara
authors.initials: MB
authors.lastname: Schaefer
authors.affiliation: Department of Internal Medicine II, University Hospital of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.
authors.forename: Christian Alexander
authors.initials: CA
authors.lastname: Schaefer
authors.affiliation: Department of Internal Medicine I, University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Schifferings
authors.affiliation: International Neuroscience Institute, INI Hannover GmbH, Rudolf Pichlmayr Str. 4, 30625, Hannover, Germany.
authors.forename: Christoph Rüdiger Wolfram
authors.initials: CR
authors.lastname: Kuhlmann
authors.affiliation: Department of Anaesthesiology, University of Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany.
authors.forename: Annett
authors.initials: A
authors.lastname: Urban
authors.affiliation: German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
authors.forename: Utz
authors.initials: U
authors.lastname: Benscheid
authors.affiliation: Department of Anaesthesiology, University Hospital of Giessen and Marburg, Giessen, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Fischer
authors.affiliation: University of Giessen Lung Center (UGLC), University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hecker
authors.affiliation: Department of Lung Development and Remodelling, Max-Planck-Institute, Parkstr. 1, 61231, Bad Nauheim, Germany.
authors.forename: Rory E
authors.initials: RE
authors.lastname: Morty
authors.affiliation: University of Giessen Lung Center (UGLC), University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany.
authors.forename: Istvan
authors.initials: I
authors.lastname: Vadasz
authors.affiliation: University of Giessen Lung Center (UGLC), University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Herold
authors.affiliation: Department of Pneumology, Charité, University of Berlin, Chariteplatz 1, 10117, Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Witzenrath
authors.affiliation: University of Giessen Lung Center (UGLC), University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Seeger
authors.affiliation: Department of Internal Medicine I, University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany.
authors.forename: Ali
authors.initials: A
authors.lastname: Erdogan
authors.affiliation: University of Giessen Lung Center (UGLC), University Hospital of Giessen and Marburg, Klinikstr. 33, 35392, Giessen, Germany. Konstantin.Mayer@innere.med.uni-giessen.de.
authors.forename: Konstantin
authors.identifier: http://orcid.org/0000-0002-6565-2187
authors.initials: K
authors.lastname: Mayer
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D016718:Arachidonic Acid / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D006801:Humans; D021962:Membrane Microdomains / Q000187:drug effects* / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D015703:Antigens, CD; D014409:Tumor Necrosis Factor-alpha; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid
keywords: Adhesion; Calcium; Fatty acids; Inflammation; Lipid rafts