title: Electrophilic nitro-fatty acids inhibit vascular inflammation by disrupting LPS-dependent TLR4 signalling in lipid rafts.
abstract: OBJECTIVE
  Electrophilic fatty acid nitroalkene derivatives, products of unsaturated fatty acid nitration, exert long-term cardiovascular protection in experimental models of metabolic and cardiovascular diseases. The goal of this study is to examine the effects of nitro-fatty acids in the regulation of upstream signalling events in nuclear factor-κB (NF-κB) activation and determine whether low-dose acute administration of nitro-fatty acids reduces vascular inflammation in vivo.
  
  
  RESULTS
  Using NF-κB-luciferase transgenic mice, it was determined that pre-emptive treatment with nitro-oleic acid (OA-NO2), but not oleic acid (OA) inhibits lipopolysaccharide (LPS)-induced NF-κB activation both in vivo and in isolated macrophages. Acute intravenous administration of OA-NO2 was equally effective to inhibit leukocyte recruitment to the vascular endothelium assessed by intravital microscopy and significantly reduces aortic expression of adhesion molecules. An acute treatment with OA-NO2 in vivo yielding nanomolar concentrations in plasma, is sufficient to inhibit LPS-induced Toll-like receptor 4 (TLR4)-induced cell surface expression in leukocytes and NF-κB activation. In vitro experiments reveal that OA-NO2 suppresses LPS-induced TLR4 signalling, inhibitor of κB (IκBα) phosphorylation and ubiquitination, phosphorylation of the IκB kinase (IKK), impairing the recruitment of the TLR4 and TNF receptor associated factor 6 (TRAF6) to the lipid rafts compartments.
  
  
  CONCLUSIONS
  These studies demonstrate that acute administration of nitro-fatty acids is effective to reduce vascular inflammation in vivo. These findings reveal a direct role of nitro-fatty acids in the disruption of the TLR4 signalling complex in lipid rafts, upstream events of the NF-κB pathway, leading to resolution of pro-inflammatory activation of NF-κB in the vasculature.
authors: Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, North Campus Research Complex Building 26 Room 355S, 2800 Plymouth Road, Ann Arbor, MI, USA. luisvill@umich.edu
authors: Luis
authors: L
authors: Villacorta
authors: Lin
authors: L
authors: Chang
authors: Sonia R
authors: SR
authors: Salvatore
authors: Tomonaga
authors: T
authors: Ichikawa
authors: Jifeng
authors: J
authors: Zhang
authors: Danica
authors: D
authors: Petrovic-Djergovic
authors: Lingyun
authors: L
authors: Jia
authors: Harald
authors: H
authors: Carlsen
authors: Francisco J
authors: FJ
authors: Schopfer
authors: Bruce A
authors: BA
authors: Freeman
authors: Y Eugene
authors: YE
authors: Chen
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D021962:Membrane Microdomains / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000494:pharmacology*; D009829:Oleic Acids / Q000494:pharmacology*; D010766:Phosphorylation; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology*; D051197:Toll-Like Receptor 4 / Q000032:analysis / Q000502:physiology*; D014657:Vasculitis / Q000517:prevention & control*
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D009829:Oleic Acids; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D009569:Nitric Oxide