title: Effect of NF-κB decoy on insulin resistance of adipocytes from patients with type 2 diabetes mellitus.
abstract: OBJECTIVE
  This study aimed to investigate whether NF-κB contributes to insulin resistance in type 2 diabetes (T2DM).
  
  
  METHODS
  Subcutaneous abdominal adipose tissue was obtained from T2DM patients and non-diabetic control subjects. Pre-adipocytes were cultured and differentiated into adipocytes in vitro. Upon insulin stimulation, IRS-1 tyrosine and AKT (Ser473) phosphorylation were examined by immunoprecipitation and immunoblotting, while levels of inflammatory mediators IL-6 and MCP-1, and the DNA-binding activity of NF-κB, were examined by ELISA and electrophoretic mobility shift assay (EMSA), respectively. NF-κB decoy molecules were introduced into T2DM adipocytes, and their effects on all these molecular events evaluated.
  
  
  RESULTS
  Compared with cells from non-diabetic subjects, adipocytes from T2DM patients showed signs of insulin resistance, with significantly reduced IRS-1 tyrosine and AKT (Ser 473) phosphorylation levels in response to insulin stimulation. At the same time, T2DM cells displayed elevated levels of IL-6 and MCP-1, and NF-κB activity. Introduction of NF-κB decoy molecules significantly inhibited both IL-6 secretion and NF-κB activity, while enhancing insulin-stimulated IRS-1 tyrosine and AKT (Ser473) phosphorylation in T2DM adipocytes.
  
  
  CONCLUSIONS
  Abdominal subcutaneous fat cells from T2DM patients display signs of insulin resistance and microinflammatory status. NF-κB decoy molecules inhibited NF-κB overactivation and also partly reversed insulin resistance. These results provide evidence of a link between inflammation and insulin resistance in T2DM cells, suggesting a potential contribution of inflammation to the mechanism of insulin resistance.
authors.affiliation: Internal Medicine, Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China. lzok92@163.com
authors.forename: L
authors.initials: L
authors.lastname: Zhong
authors.forename: Y
authors.initials: Y
authors.lastname: Luo
authors.forename: C
authors.initials: C
authors.lastname: Huang
authors.forename: L
authors.initials: L
authors.lastname: Liu
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D050507:Subcutaneous Fat, Abdominal / Q000378:metabolism*
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2; C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; D015850:Interleukin-6; D016328:NF-kappa B; C468119:NF-kappaB decoy; D009838:Oligodeoxyribonucleotides; D051057:Proto-Oncogene Proteins c-akt