title: Electrophilic fatty acid species inhibit 5-lipoxygenase and attenuate sepsis-induced pulmonary inflammation.
abstract: OBJECTIVE
  The reaction of nitric oxide and nitrite-derived species with polyunsaturated fatty acids yields electrophilic fatty acid nitroalkene derivatives (NO2-FA), which display anti-inflammatory properties. Given that the 5-lipoxygenase (5-LO, ALOX5) possesses critical nucleophilic amino acids, which are potentially sensitive to electrophilic modifications, we determined the consequences of NO2-FA on 5-LO activity in vitro and on 5-LO-mediated inflammation in vivo.
  
  
  RESULTS
  Stimulation of human polymorphonuclear leukocytes (PMNL) with nitro-oleic (NO2-OA) or nitro-linoleic acid (NO2-LA) (but not the parent lipids) resulted in the concentration-dependent and irreversible inhibition of 5-LO activity. Similar effects were observed in cell lysates and using the recombinant human protein, indicating a direct reaction with 5-LO. NO2-FAs did not affect the activity of the platelet-type 12-LO (ALOX12) or 15-LO-1 (ALOX15) in intact cells or the recombinant protein. The NO2-FA-induced inhibition of 5-LO was attributed to the alkylation of Cys418, and the exchange of Cys418 to serine rendered 5-LO insensitive to NO2-FA. In vivo, the systemic administration of NO2-OA to mice decreased neutrophil and monocyte mobilization in response to lipopolysaccharide (LPS), attenuated the formation of the 5-LO product 5-hydroxyeicosatetraenoic acid (5-HETE), and inhibited lung injury. The administration of NO2-OA to 5-LO knockout mice had no effect on LPS-induced neutrophil or monocyte mobilization as well as on lung injury.
  
  
  METHODS
  Prophylactic administration of NO2-OA to septic mice inhibits inflammation and promotes its resolution by interfering in 5-LO-mediated inflammatory processes.
  
  
  CONCLUSIONS
  NO2-FAs directly and irreversibly inhibit 5-LO and attenuate downstream acute inflammatory responses.
authors.affiliation: 1 Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University , Frankfurt am Main, Germany .
authors.forename: Khader
authors.initials: K
authors.lastname: Awwad
authors.forename: Svenja D
authors.initials: SD
authors.lastname: Steinbrink
authors.forename: Timo
authors.initials: T
authors.lastname: Frömel
authors.forename: Nicole
authors.initials: N
authors.lastname: Lill
authors.forename: Johann
authors.initials: J
authors.lastname: Isaak
authors.forename: Ann-Kathrin
authors.initials: AK
authors.lastname: Häfner
authors.forename: Jessica
authors.initials: J
authors.lastname: Roos
authors.forename: Bettina
authors.initials: B
authors.lastname: Hofmann
authors.forename: Heinrich
authors.initials: H
authors.lastname: Heide
authors.forename: Gerd
authors.initials: G
authors.lastname: Geisslinger
authors.forename: Dieter
authors.initials: D
authors.lastname: Steinhilber
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Freeman
authors.forename: Thorsten J
authors.initials: TJ
authors.lastname: Maier
authors.forename: Ingrid
authors.initials: I
authors.lastname: Fleming
mesh_terms: D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000378:metabolism; D051379:Mice; D009504:Neutrophils / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D011014:Pneumonia / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D018805:Sepsis / Q000150:complications / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D015398:Signal Transduction / Q000235:genetics
chemical_list: D005231:Fatty Acids, Unsaturated; D016859:Lipoxygenase Inhibitors; D009569:Nitric Oxide; D001094:Arachidonate 5-Lipoxygenase