title: O-GlcNAc modification of NFκB p65 inhibits TNF-α-induced inflammatory mediator expression in rat aortic smooth muscle cells.
abstract: BACKGROUND
  We have shown that glucosamine (GlcN) or O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc) treatment augments O-linked-N-acetylglucosamine (O-GlcNAc) protein modification and attenuates inflammatory mediator expression, leukocyte infiltration and neointima formation in balloon injured rat carotid arteries and have identified the arterial smooth muscle cell (SMC) as the target cell in the injury response. NFκB signaling has been shown to mediate the expression of inflammatory genes and neointima formation in injured arteries. Phosphorylation of the p65 subunit of NFκB is required for the transcriptional activation of NFκB. This study tested the hypothesis that GlcN or PUGNAc treatment protects vascular SMCs against tumor necrosis factor (TNF)-α induced inflammatory stress by enhancing O-GlcNAcylation and inhibiting TNF-α induced phosphorylation of NFκB p65, thus inhibiting NFκB signaling.
  
  
  RESULTS
  Quiescent rat aortic SMCs were pretreated with GlcN (5 mM), PUGNAc (10(-4) M) or vehicle and then stimulated with TNF-α (10 ng/ml). Both treatments inhibited TNF-α-induced expression of chemokines [cytokine-induced neutrophil chemoattractant (CINC)-2β and monocyte chemotactic protein (MCP)-1] and adhesion molecules [vascular cell adhesion molecule (VCAM)-1 and P-Selectin]. Both treatments inhibited TNF-α induced NFκB p65 activation and promoter activity, increased NFκB p65 O-GlcNAcylation and inhibited NFκB p65 phosphorylation at Serine 536, thus promoting IκBα binding to NFκB p65.
  
  
  CONCLUSIONS
  There is a reciprocal relationship between O-GlcNAcylation and phosphorylation of NFκB p65, such that increased NFκB p65 O-GlcNAc modification inhibits TNF-α-Induced expression of inflammatory mediators through inhibition of NFκB p65 signaling. These findings provide a mechanistic basis for our previous observations that GlcN and PUGNAc treatments inhibit inflammation and remodeling induced by acute endoluminal arterial injury.
authors: Vascular Biology and Hypertension Program, Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America. dqxing@uab.edu
authors: Dongqi
authors: D
authors: Xing
authors: Kaizheng
authors: K
authors: Gong
authors: Wenguang
authors: W
authors: Feng
authors: Susan E
authors: SE
authors: Nozell
authors: Yiu-Fai
authors: YF
authors: Chen
authors: John C
authors: JC
authors: Chatham
authors: Suzanne
authors: S
authors: Oparil
mesh_terms: D000117:Acetylglucosamine / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000166:cytology*; D015153:Blotting, Western; D002478:Cells, Cultured; D047468:Immunoprecipitation; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D010091:Oximes / Q000494:pharmacology; D048448:Phenylcarbamates / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D051996:Transcription Factor RelA / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D010091:Oximes; D048448:Phenylcarbamates; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; C068836:N-acetylglucosaminono-1,5-lactone O-(phenylcarbamoyl)oxime; D000117:Acetylglucosamine