title: O-GlcNAcylation and p50/p105 binding of c-Rel are dynamically regulated by LPS and glucosamine in BV2 microglia cells.
abstract: OBJECTIVE
  Previously, we demonstrated that glucosamine (GlcN) exerts a suppressive effect on LPS-induced inducible NOS (iNOS) through the inhibition of NF-κB activation in BV2 mouse microglial cells. The purpose of the present study was to examine the mechanisms by which GlcN inhibits NF-κB activation.
  
  
  METHODS
  BV2 cells were stimulated with LPS with or without GlcN. NF-κB/c-Rel activities were studied by EMSA, nuclear translocation, reporter assay or chromatin immunoprecipitation. Wheat germ agglutinin precipitation or galactosyltransferase assay were used to measure O-linked N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) of c-Rel. Protein-protein interactions were examined by co-immunoprecipitation.
  
  
  RESULTS
  LPS stimulated the activation of c-Rel, increased the O-GlcNAcylation of c-Rel and enhanced the binding of c-Rel to the NF-κB site in the iNOS promoter; GlcN attenuated these effects of LPS. O-GlcNAcylation of both nuclear and cytosolic forms of c-Rel was increased by LPS and reduced by GlcN. LPS increased the interaction of c-Rel with O-GlcNAc transferase (OGT) and p50/p105, and GlcN suppressed these interactions. Knockdown of OGT reduced the c-Rel O-GlcNAcylation and c-Rel-p50 interaction in response to LPS, but did not affect either the binding of c-Rel to the iNOS promoter or the transcriptional activity of c-Rel.
  
  
  CONCLUSIONS
  In BV2 microglial cells, the anti-inflammatory effect of GlcN is mediated by prevention of the prolonged activation of transcription factors, c-Rel and NF-κB. Further clarification of the mechanism by which GlcN exerts this effect will facilitate the development of pharmacological strategies for preventing excessive NO formation when targeting inflammatory diseases of the periphery or CNS.
authors: Department of Physiology and Biophysics, College of Medicine, Inha University, Incheon, Korea.
authors: So-Young
authors: SY
authors: Hwang
authors: Ji-Sun
authors: JS
authors: Hwang
authors: Song-Yi
authors: SY
authors: Kim
authors: Inn-Oc
authors: IO
authors: Han
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D000215:Acylation / Q000187:drug effects*; D000818:Animals; D002460:Cell Line; D005786:Gene Expression Regulation; D005944:Glucosamine / Q000737:chemistry / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D017628:Microglia / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020569:Proto-Oncogene Proteins c-rel / Q000378:metabolism*
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D020569:Proto-Oncogene Proteins c-rel; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D005944:Glucosamine; D000117:Acetylglucosamine
keywords: LPS; O-GlcNAc; OGT; c-Rel; glucosamine
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