title: Human Endothelial Cell Activation by Escherichia coli and Staphylococcus aureus Is Mediated by TNF and IL-1β Secondarily to Activation of C5 and CD14 in Whole Blood.
abstract: Endothelial cells (EC) play a central role in inflammation. E-selectin and ICAM-1 expression are essential for leukocyte recruitment and are good markers of EC activation. Most studies of EC activation are done in vitro using isolated mediators. The aim of the present study was to examine the relative importance of pattern recognition systems and downstream mediators in bacteria-induced EC activation in a physiological relevant human model, using EC incubated with whole blood. HUVEC were incubated with human whole blood. Escherichia coli- and Staphylococcus aureus-induced EC activation was measured by E-selectin and ICAM-1 expression using flow cytometry. The mAb 18D11 was used to neutralize CD14, and the lipid A analog eritoran was used to block TLR4/MD2. C5 cleavage was inhibited using eculizumab, and C5aR1 was blocked by an antagonist. Infliximab and canakinumab were used to neutralize TNF and IL-1β. The EC were minimally activated when bacteria were incubated in serum, whereas a substantial EC activation was seen when the bacteria were incubated in whole blood. E. coli-induced activation was largely CD14-dependent, whereas S. aureus mainly caused a C5aR1-mediated response. Combined CD14 and C5 inhibition reduced E-selectin and ICAM-1 expression by 96 and 98% for E. coli and by 70 and 75% for S. aureus. Finally, the EC activation by both bacteria was completely abolished by combined inhibition of TNF and IL-1β. E. coli and S. aureus activated EC in a CD14- and C5-dependent manner with subsequent leukocyte secretion of TNF and IL-1β mediating the effect.
authors.affiliation: Research Laboratory, Nordland Hospital, 8092 Bodø, Norway; Faculty of Health Sciences, K. G. Jebsen Thrombosis Research and Expertise Center, University of Tromsø, 9037 Tromsø, Norway; Department of Immunology, Oslo University Hospital, Rikshospitalet, University of Oslo, 0424 Oslo, Norway; K. G. Jebsen Inflammation Research Center, University of Oslo, 0424 Oslo, Norway;
authors.forename: Stig
authors.initials: S
authors.lastname: Nymo
authors.affiliation: Department of Immunology, Oslo University Hospital, Rikshospitalet, University of Oslo, 0424 Oslo, Norway; K. G. Jebsen Inflammation Research Center, University of Oslo, 0424 Oslo, Norway;
authors.forename: Alice
authors.identifier: http://orcid.org/0000-0003-2276-766X
authors.initials: A
authors.lastname: Gustavsen
authors.affiliation: Department of Immunology, Oslo University Hospital, Rikshospitalet, University of Oslo, 0424 Oslo, Norway; K. G. Jebsen Inflammation Research Center, University of Oslo, 0424 Oslo, Norway;
authors.forename: Per H
authors.identifier: http://orcid.org/0000-0002-7192-5794
authors.initials: PH
authors.lastname: Nilsson
authors.affiliation: Research Laboratory, Nordland Hospital, 8092 Bodø, Norway; Faculty of Health Sciences, K. G. Jebsen Thrombosis Research and Expertise Center, University of Tromsø, 9037 Tromsø, Norway;
authors.forename: Corinna
authors.identifier: http://orcid.org/0000-0003-1750-8065
authors.initials: C
authors.lastname: Lau
authors.affiliation: Center of Molecular Inflammation Research, Norwegian University of Science and Technology, 7491 Trondheim, Norway; and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
authors.forename: Terje
authors.initials: T
authors.lastname: Espevik
authors.affiliation: Research Laboratory, Nordland Hospital, 8092 Bodø, Norway; Faculty of Health Sciences, K. G. Jebsen Thrombosis Research and Expertise Center, University of Tromsø, 9037 Tromsø, Norway; Department of Immunology, Oslo University Hospital, Rikshospitalet, University of Oslo, 0424 Oslo, Norway; K. G. Jebsen Inflammation Research Center, University of Oslo, 0424 Oslo, Norway; Center of Molecular Inflammation Research, Norwegian University of Science and Technology, 7491 Trondheim, Norway; and t.e.mollnes@medisin.uio.no.
authors.forename: Tom Eirik
authors.initials: TE
authors.lastname: Mollnes
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015415:Biomarkers; D002478:Cells, Cultured; D003167:Complement Activation / Q000276:immunology*; D003182:Complement C5 / Q000037:antagonists & inhibitors / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004926:Escherichia coli / Q000276:immunology*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D051218:Lymphocyte Antigen 96 / Q000037:antagonists & inhibitors / Q000378:metabolism; D013211:Staphylococcus aureus / Q000276:immunology*; D048069:Tumor Necrosis Factors / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D003182:Complement C5; D016207:Cytokines; D053583:Interleukin-1beta; D018950:Lipopolysaccharide Receptors; D051218:Lymphocyte Antigen 96; D048069:Tumor Necrosis Factors