title: S-nitrosated α-1-acid glycoprotein kills drug-resistant bacteria and aids survival in sepsis.
abstract: Treating infections with exogenous NO, which shows broad-spectrum antimicrobial activity, appears to be effective. Similar to NO biosynthesis, biosynthesis of α-1-acid glycoprotein variant A (AGPa), with a reduced cysteine (Cys149), increases markedly during inflammation and infection. We hypothesized that AGPa is an S-nitrosation target in acute-phase proteins. This study aimed to determine whether S-nitrosated AGPa (SNO-AGPa) may be the first compound of this novel antibacterial class against multidrug-resistant bacteria. AGPa was incubated with RAW264.7 cells activated by lipopolysaccharide and interferon-γ. The antimicrobial effects of SNO-AGPa were determined by measuring the turbidity of the bacterial suspensions in vitro and survival in a murine sepsis model in vivo, respectively. Results indicated that endogenous NO generated by activated RAW264.7 cells caused S-nitrosation of AGPa at Cys149. SNO-AGPa strongly inhibited growth of gram-positive, gram-negative, and multidrug-resistant bacteria and was an extremely potent bacteriostatic compound (IC(50): 10(-9) to 10(-6) M). The antibacterial mechanism of SNO-AGPa involves S-transnitrosation from SNO-AGPa to bacterial cells. Treatment with SNO-AGPa, but not with AGPa, markedly reduced bacterial counts in blood and liver in a mouse sepsis model. The sialyl residues of AGPa seem to suppress the antibacterial activity, since SNO-asialo AGPa was more potent than SNO-AGPa.
authors.affiliation: Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Watanabe
authors.forename: Yu
authors.initials: Y
authors.lastname: Ishima
authors.forename: Takaaki
authors.initials: T
authors.lastname: Akaike
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sawa
authors.forename: Teruo
authors.initials: T
authors.lastname: Kuroda
authors.forename: Wakano
authors.initials: W
authors.lastname: Ogawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Ayaka
authors.initials: A
authors.lastname: Suenaga
authors.forename: Toshiya
authors.initials: T
authors.lastname: Kai
authors.forename: Masaki
authors.initials: M
authors.lastname: Otagiri
authors.forename: Toru
authors.initials: T
authors.lastname: Maruyama
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects*; D002460:Cell Line; D004352:Drug Resistance, Microbial; D051379:Mice; D015538:Nitrosation; D009961:Orosomucoid / Q000494:pharmacology*; D018805:Sepsis / Q000382:microbiology / Q000503:physiopathology*; D015996:Survival Rate
chemical_list: D009961:Orosomucoid