Advanced glycation end products (AGEs) have known to exert the inflammatory response by stimulating the pattern recognition receptors. Previously, we found that AGEs directly interact with TWEAK, and inhibited its action. This finding raised the possibility that AGEs will alter the function of other cytokines through direct interaction. To investigate this possibility, we performed the comprehensive screening for candidates capable of interacting with AGEs using protein array analysis. The array analysis revealed that HMGB1 had a markedly high affinity for AGEs. HMGB1 is the representative proinflammatory DAMPs molecule, and is reported to interact with LPS directly to exert its inflammatory function. When LPS, HMGB1, and AGEs were mixed, the mobility of HMGB1 had shifted significantly in native PAGE, suggesting that these three molecules formed a triplet complex. The addition of AGEs to the LPS-HMGB1 mixture synergistically enhanced LPS-HMGB1-induced TNF-α mRNA expression in macrophage-like RAW264.7 cells. In addition, using receptor knockout clones, the increased proinflammatory response by LPS-HMGB1-AGEs complex was demonstrated to be mediated via TLR-4 and RAGE. This findings suggested that AGEs played the pathophysiological roles by potentiating the LPS-HMGB1-stimulated proinflammatory response through direct interactions.
