title: Bacillus anthracis-derived nitric oxide induces protein S-nitrosylation contributing to macrophage death.
abstract: Bacillus anthracis, a causative agent of anthrax, is able to germinate and survive within macrophages. A recent study suggested that B. anthracis-derived nitric oxide (bNO) is a key aspect of bacterial defense that protects bacterial DNA from oxidative burst in the macrophages. However, the virulent effect of bNO in host cells has not been investigated. Here, we report that bNO contributes macrophage killing by S-nitrosylation of bioenergetic-relating proteins within mitochondria. Toxigenic Sterne induces expression of the bnos gene and produces bNO during early stage of infection. Nitroso-proteomic analysis coupled with a biotin-switch technique demonstrated that toxigenic infection induces protein S-nitrosylation in B. anthracis-susceptible RAW264.7. For each target enzyme tested (complex I, complex III and complex IV), infection by B. anthracis Sterne caused enzyme inhibition. Nω-nitro-L-arginine methyl ester, a NO synthase inhibitor, reduced S-nitrosylation and partially restored cell viability evaluated by intracellular ATP levels in macrophages. Our data suggest that bNO leads to energy depletion driven by impaired mitochondrial bioenergetic machinery that ultimately contributes to macrophage death. This novel mechanism of anthrax pathogenesis may offer specific approach to the development of therapeutics.
authors.affiliation: School of Systems Biology, National Center for Biodefense and Infectious Diseases, George Mason University, 10650 Pyramid Place, Manassas, VA 20110, United States. mchung3@gmu.edu
authors.forename: Myung-Chul
authors.initials: MC
authors.lastname: Chung
authors.forename: Aarthi
authors.initials: A
authors.lastname: Narayanan
authors.forename: Taissia G
authors.initials: TG
authors.lastname: Popova
authors.forename: Fatah
authors.initials: F
authors.lastname: Kashanchi
authors.forename: Charles L
authors.initials: CL
authors.lastname: Bailey
authors.forename: Serguei G
authors.initials: SG
authors.lastname: Popov
mesh_terms: D000818:Animals; D000881:Anthrax / Q000201:enzymology / Q000276:immunology* / Q000382:microbiology; D017209:Apoptosis / Q000276:immunology*; D001408:Bacillus anthracis / Q000378:metabolism / Q000472:pathogenicity*; D002460:Cell Line; D042967:Electron Transport Complex I / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D015870:Gene Expression; D008264:Macrophages / Q000201:enzymology / Q000382:microbiology*; D051379:Mice; D008928:Mitochondria / Q000201:enzymology / Q000382:microbiology*; D009569:Nitric Oxide / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*
chemical_list: D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D003576:Electron Transport Complex IV; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III