title: Contribution of the platelet activating factor signaling pathway to cerebral microcirculatory dysfunction during experimental sepsis by ExoU producing Pseudomonas aeruginosa.
abstract: Intravital microscopy was used to assess the involvement of ExoU, a Pseudomonas aeruginosa cytotoxin with phospholipase A2 activity, in dysfunction of cerebral microcirculation during experimental pneumosepsis. Cortical vessels from mice intratracheally infected with low density of the ExoU-producing PA103 P. aeruginosa strain exhibited increased leukocyte rolling and adhesion to venule endothelium, decreased capillar density and impaired arteriolar response to vasoactive acetylcholine. These phenomena were mediated by the platelet activating factor receptor (PAFR) pathway because they were reversed in mice treated with a PAFR antagonist prior to infection. Brains from PA103-infected animals exhibited a perivascular inflammatory infiltration that was not detected in animals infected with an exoU deficient mutant or in mice treated with the PAFR antagonist and infected with the wild type bacteria. No effect on brain capillary density was detected in mice infected with the PAO1 P. aeruginosa strain, which do not produce ExoU. Finally, after PA103 infection, mice with a targeted deletion of the PAFR gene exhibited higher brain capillary density and lower leukocyte adhesion to venule endothelium, as well as lower increase of systemic inflammatory cytokines, when compared to wild-type mice. Altogether, our results establish a role for PAFR in mediating ExoU-induced cerebral microvascular failure in a murine model of sepsis.
authors.affiliation: Department of Microbiology, Immunology and Parasitology, State University of Rio de Janeiro, 20551-30 Rio de Janeiro, Brazil crisplot77@gmail.com.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Plotkowski
authors.affiliation: Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, Rio de Janeiro, 21045-900, Brazil.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Estato
authors.affiliation: Department of Microbiology, Immunology and Parasitology, State University of Rio de Janeiro, 20551-30 Rio de Janeiro, Brazil.
authors.forename: Sabrina Alves
authors.initials: SA
authors.lastname: Santos
authors.affiliation: Department of Veterinary Medicine, Federal University of Bahia, Salvador, 40170-110, Brazil.
authors.forename: Mauricio Costa Alves
authors.initials: MC
authors.lastname: da Silva
authors.affiliation: Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, 31270-901, Brazil.
authors.forename: Aline Silva
authors.initials: AS
authors.lastname: Miranda
authors.affiliation: Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, 31270-901, Brazil.
authors.forename: Pedro Elias
authors.initials: PE
authors.lastname: de Miranda
authors.affiliation: Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, 31270-901, Brazil.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Pinho
authors.affiliation: Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, Rio de Janeiro, 21045-900, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tibiriça
authors.affiliation: Department of Cell Biology, State University of Rio de Janeiro, Rio de Janeiro, 20550-013, Brazil.
authors.forename: Verônica
authors.initials: V
authors.lastname: Morandi
authors.affiliation: Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, 31270-901, Brazil.
authors.forename: Mauro Martins
authors.initials: MM
authors.lastname: Teixeira
authors.affiliation: Department of Pathology, State University of Rio de Janeiro, Rio de Janeiro, 22551-030, Brazil.
authors.forename: Albanita
authors.initials: A
authors.lastname: Vianna
authors.affiliation: Department of Microbiology, Immunology and Parasitology, State University of Rio de Janeiro, 20551-30 Rio de Janeiro, Brazil.
authors.forename: Alessandra Mattos
authors.initials: AM
authors.lastname: Saliba
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D001921:Brain / Q000473:pathology*; D002448:Cell Adhesion; D016207:Cytokines / Q000032:analysis; D005260:Female; D000069416:Intravital Microscopy; D007962:Leukocytes / Q000276:immunology; D051379:Mice; D008833:Microcirculation / Q000502:physiology*; D010972:Platelet Activating Factor / Q000378:metabolism*; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D011552:Pseudomonas Infections / Q000473:pathology*; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D018805:Sepsis / Q000473:pathology*; D015398:Signal Transduction
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D010972:Platelet Activating Factor; D010980:Platelet Membrane Glycoproteins; D043562:Receptors, G-Protein-Coupled; C039351:platelet activating factor receptor; C111749:pseudomonas exoprotein A protein, Pseudomonas aeruginosa
keywords: PAF–PAFR signaling pathway; Pseudomonas aeruginosa type III secretion toxin; cerebral intravital microscopy; cerebral microvascular failure; experimental Pseudomonas aeruginosa sepsis