title: Lipoteichoic acid from Staphylococcus aureus induces lung endothelial cell barrier dysfunction: role of reactive oxygen and nitrogen species.
abstract: Tunneled central venous catheters (TCVCs) are used for dialysis access in 82% of new hemodialysis patients and are rapidly colonized with Gram-positive organism (e.g. Staphylococcus aureus) biofilm, a source of recurrent infections and chronic inflammation. Lipoteichoic acid (LTA), a cell wall ribitol polymer from Gram-positive organisms, mediates inflammation through the Toll-like receptor 2 (TLR2). The effect of LTA on lung endothelial permeability is not known. We tested the hypothesis that LTA from Staphylococcus aureus induces alterations in the permeability of pulmonary microvessel endothelial monolayers (PMEM) that result from activation of TLR2 and are mediated by reactive oxygen/nitrogen species (RONS). The permeability of PMEM was assessed by the clearance rate of Evans blue-labeled albumin, the activation of the TLR2 pathway was assessed by Western blot, and the generation of RONS was measured by the fluorescence of oxidized dihydroethidium and a dichlorofluorescein derivative. Treatment with LTA or the TLR2 agonist Pam((3))CSK((4)) induced significant increases in albumin permeability, IκBα phosphorylation, IRAK1 degradation, RONS generation, and endothelial nitric oxide synthase (eNOS) activation (as measured by the p-eNOS(ser1177):p-eNOS(thr495) ratio). The effects on permeability and RONS were effectively prevented by co-administration of the superoxide scavenger Tiron, the peroxynitrite scavenger Urate, or the eNOS inhibitor L-NAME and these effects as well as eNOS activation were reduced or prevented by pretreatment with an IRAK1/4 inhibitor. The results indicate that the activation of TLR2 and the generation of ROS/RNS mediates LTA-induced barrier dysfunction in PMEM.
authors.affiliation: Department of Pharmacy Practice, Albany College of Pharmacy and Health Sciences, Albany, New York, USA. amy.bartonpai@acphs.edu
authors.forename: Amy Barton
authors.initials: AB
authors.lastname: Pai
authors.forename: Heena
authors.initials: H
authors.lastname: Patel
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Prokopienko
authors.forename: Hiba
authors.initials: H
authors.lastname: Alsaffar
authors.forename: Nancy
authors.initials: N
authors.lastname: Gertzberg
authors.forename: Paul
authors.initials: P
authors.lastname: Neumann
authors.forename: Anjoli
authors.initials: A
authors.lastname: Punjabi
authors.forename: Arnold
authors.initials: A
authors.lastname: Johnson
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D015153:Blotting, Western; D062905:Central Venous Catheters / Q000382:microbiology*; D042783:Endothelial Cells / Q000378:metabolism*; D005070:Evans Blue; D005453:Fluorescence; D006801:Humans; D015151:Immunoblotting; D008070:Lipopolysaccharides / Q000633:toxicity*; D008168:Lung / Q000166:cytology* / Q000187:drug effects; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010539:Permeability / Q000187:drug effects*; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D006435:Renal Dialysis / Q000009:adverse effects*; D013211:Staphylococcus aureus / Q000378:metabolism*; D013682:Teichoic Acids / Q000633:toxicity*; D051195:Toll-Like Receptor 2 / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; C495342:TLR2 protein, human; D013682:Teichoic Acids; D051195:Toll-Like Receptor 2; D005070:Evans Blue; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; C009900:lipoteichoic acid; D052250:Nitric Oxide Synthase Type III