TLR4 and RAGE: similar routes leading to inflammation in type 2 diabetic patients

Diabetes Metab. 2011 Sep;37(4):336-42. doi: 10.1016/j.diabet.2010.12.005. Epub 2011 Mar 4.


Aim: The present study investigates the interaction of TLR4 and RAGE with their respective ligands as inducers of the inflammatory markers IL-6 and TNF-α. Also, the reactivity of peripheral blood mononuclear cells (PBMNC) from type 2 diabetic (T2D) patients and non-diabetic healthy controls (ND) were comparatively studied.

Methods: Concentrations of IL-6 and TNF-α were measured by sandwich Elisa, using kits supplied by Assay Designs (Ann Arbor, MI, USA). PBMNC from T2D and ND were incubated in the presence or absence of LPS, anti-TLR4 or anti-RAGE for 72 hours at 37°C under 5% CO(2). The final volume was adjusted to 300 μL in DMEM supplemented with 10% fetal bovine serum. After incubation, the cells were centrifuged, the supernatant collected and the cytokines measured.

Results: PBMNC from T2D were more sensitive to innate immune stimulation with LPS and monoclonal agonist anti-TLR4 than were cells from ND. The actions of LPS, anti-TLR4 and anti-RAGE potentiated the production of IL-6 and TNF-α in both groups. The simultaneous activation of monoclonal anti-RAGE and anti-TLR4 suggests that both antibodies used different receptors on the cell surface, but converged on the same PBMNC signaling metabolic pathways. This simultaneous activation induced a higher production of IL-6 and TNF-α in PBMNC from the T2D patients than from the ND subjects.

Conclusion: Our results clearly show an exacerbation of innate immunity in PBMNC with T2D that was possibly hyperglycaemia-induced. These data, when analyzed together, suggest the importance of innate immunity in the pathogenesis of T2D.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology
  • Case-Control Studies
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / metabolism*
  • Humans
  • Inflammation / metabolism*
  • Interleukin-6 / biosynthesis
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / metabolism
  • Lipopolysaccharides / pharmacology
  • Middle Aged
  • Receptor for Advanced Glycation End Products / immunology
  • Receptor for Advanced Glycation End Products / metabolism*
  • Signal Transduction / drug effects
  • Toll-Like Receptor 4 / agonists
  • Toll-Like Receptor 4 / antagonists & inhibitors
  • Toll-Like Receptor 4 / immunology
  • Toll-Like Receptor 4 / metabolism*
  • Tumor Necrosis Factor-alpha / biosynthesis


  • Antibodies, Monoclonal
  • Interleukin-6
  • Lipopolysaccharides
  • Receptor for Advanced Glycation End Products
  • TLR4 protein, human
  • Toll-Like Receptor 4
  • Tumor Necrosis Factor-alpha