title: Cytotoxic effects of the lipopolysaccharide from Pseudomonas fluorescens on neurons and glial cells.
abstract: Pseudomonas fluorescens is an emerging pathogen closely related to Pseudomonas aeruginosa. In the present study, the effect of the lipopolysaccharide (LPS) from P. fluorescens MF37 was investigated using indicators of apoptosis and necrosis and was compared to the effect of the LPS from P. aeruginosa PAO1. Capillary electrophoresis analysis of the LPS from P. fluorescens MF37 revealed the existence of three forms of the endotoxin and the absence of homology with the LPS from P. aeruginosa. In neurons and glial cells the LPS from P. fluorescens induced major morphological changes including a condensation of the cytoplasmic proteins, a leakage of the cytoplasmic content, the formation of blebs on the nuclear membrane and a marked reorganization of the cytoskeleton. In glial cells, the LPS from P. fluorescens provoked the migration of phosphatidylserine at the surface of the cytoplasmic membrane, a sign of apoptosis, but this reaction was associated to an increase in the permeability to propidium iodide characteristic of necrosis. Biochemical studies revealed an important activation of an inducible nitric oxide synthase and a release of lactate dehydrogenase, a stable cytosolic enzyme. These results demonstrate that the LPS from P. fluorescens induces apoptosis and a concomitant and limited necrosis, reveal the unexpected cytotoxicity of this endotoxin and provide the first demonstration of the apoptotic effect of a non-aeruginosa Pseudomonas on nerve cells.
authors.affiliation: Laboratory of Cold Microbiology, University of Rouen, UPRES 2123, 55 rue Saint Germain, 27000 Evreux, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Picot
authors.forename: Sylvie
authors.initials: S
authors.lastname: Chevalier
authors.forename: Sana
authors.initials: S
authors.lastname: Mezghani-Abdelmoula
authors.forename: Annabelle
authors.initials: A
authors.lastname: Merieau
authors.forename: Olivier
authors.initials: O
authors.lastname: Lesouhaitier
authors.forename: Philippe
authors.initials: P
authors.lastname: Leroux
authors.forename: Lionel
authors.initials: L
authors.lastname: Cazin
authors.forename: Nicole
authors.initials: N
authors.lastname: Orange
authors.forename: Marc G J
authors.initials: MG
authors.lastname: Feuilloley
mesh_terms: D000818:Animals; D017209:Apoptosis; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D019075:Electrophoresis, Capillary; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008070:Lipopolysaccharides / Q000302:isolation & purification / Q000633:toxicity*; D009336:Necrosis; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008070:Lipopolysaccharides; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase