S100B interaction with the receptor for advanced glycation end products (RAGE): a novel receptor-mediated mechanism for myocyte apoptosis postinfarction.

RATIONALE:Post-myocardial infarction ventricular remodeling is associated with the expression of a variety of factors including S100B that can potentially modulate myocyte apoptosis. OBJECTIVE:This study was undertaken to investigate the expression and function of S100B and its receptor, the receptor for advanced glycation end products in both postinfarction myocardium and in a rat neonatal myocyte culture model. METHODS AND RESULTS:In a rat model of myocardial infarction following coronary artery ligation, we demonstrate in periinfarct myocytes, upregulation of induction of S100B, and release into plasma with consequent myocyte apoptosis. Using a coimmunoprecipitation strategy, we demonstrate a direct interaction between S100B and In rat neonatal cardiac myocyte cultures, S100B at concentrations > or = 50 nmol/L induced myocyte apoptosis, as evidenced by increased terminal DNA fragmentation, TUNEL, cytochrome c release from mitochondria to cytoplasm, phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and p53, increased expression and activity of proapoptotic caspase-3, and decreased expression of antiapoptotic Bcl-2. Transfection of a full-length cDNA of or a dominant-negative mutant of duanyu1648 resulted in increased or attenuated S100B-induced myocyte apoptosis, respectively. Inhibition of ERK1/2 by U0126/PD-98059 or overexpression of a dominant negative p53 comparably inhibited S100B-induced myocyte apoptosis. CONCLUSIONS:These results suggest that interaction of duanyu1648 and its ligand S100B after myocardial infarction may play a role in myocyte apoptosis by activating ERK1/2 and p53 signaling. This receptor-mediated mechanism is uniquely amenable to therapeutic intervention.

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