title: Administration of a nitric oxide donor inhibits mglA expression by intracellular Francisella tularensis and counteracts phagosomal escape and subversion of TNF-α secretion.
abstract: Francisella tularensis is a highly virulent intracellular bacterium capable of rapid multiplication in phagocytic cells. Previous studies have revealed that activation of F. tularensis-infected macrophages leads to control of infection and reactive nitrogen and oxygen species make important contributions to the bacterial killing. We investigated the effects of adding S-nitroso-acetyl-penicillamine (SNAP), which generates nitric oxide, or 3-morpholinosydnonimine hydrochloride, which indirectly leads to formation of peroxynitrite, to J774 murine macrophage-like cell cultures infected with F. tularensis LVS. Addition of SNAP led to significantly increased colocalization between LAMP-1 and bacteria, indicating containment of F. tularensis in the phagosome within 2 h, although no killing occurred within 4 h. A specific inhibitory effect on bacterial transcription was observed since the gene encoding the global regulator MglA was inhibited 50-100-fold. F. tularensis-infected J774 cells were incapable of secreting TNF-α in response to Escherichia coli LPS but addition of SNAP almost completely reversed the suppression. Similarly, infection with an MglA mutant did not inhibit LPS-induced TNF-α secretion of J774 cells. Strong staining of nitrotyrosine was observed in SNAP-treated bacteria, and MS identified nitration of two ribosomal 50S proteins, a CBS domain pair protein and bacterioferritin. The results demonstrated that addition of SNAP initially did not affect the viability of intracellular F. tularensis LVS but led to containment of the bacteria in the phagosome. Moreover, the treatment resulted in modification by nitration of several F. tularensis proteins.
authors.affiliation: Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 85 Umeå, Sweden.
authors.forename: Linda
authors.initials: L
authors.lastname: Tancred
authors.affiliation: Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 85 Umeå, Sweden.
authors.forename: Maxim V
authors.initials: MV
authors.lastname: Telepnev
authors.affiliation: Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 85 Umeå, Sweden.
authors.forename: Igor
authors.initials: I
authors.lastname: Golovliov
authors.affiliation: Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 85 Umeå, Sweden.
authors.forename: Blanka
authors.initials: B
authors.lastname: Andersson
authors.affiliation: Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 85 Umeå, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Andersson
authors.affiliation: Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 85 Umeå, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Lindgren
authors.affiliation: Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 85 Umeå, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Sjöstedt
mesh_terms: D000818:Animals; D001212:Asialoglycoproteins / Q000235:genetics / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000276:immunology; D005604:Francisella tularensis / Q000235:genetics / Q000276:immunology*; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D051379:Mice; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000494:pharmacology; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D030421:Peroxynitrous Acid / Q000276:immunology; D012313:RNA / Q000737:chemistry / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014406:Tularemia / Q000276:immunology* / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000276:immunology
chemical_list: D001212:Asialoglycoproteins; D001426:Bacterial Proteins; C064720:Clec10a protein, mouse; D037181:Lectins, C-Type; D008565:Membrane Proteins; D020030:Nitric Oxide Donors; D014409:Tumor Necrosis Factor-alpha; D030421:Peroxynitrous Acid; C002385:linsidomine; D012313:RNA; D026423:S-Nitroso-N-Acetylpenicillamine; D008981:Molsidomine