Interactions of the receptor for advanced glycation end products (RAGE) with advanced glycation end products and S100B

RAGE is a multi-ligand pattern recognition receptor. RAGE can bind several damage associated molecular pattern proteins. RAGE- ligand interaction is pathophysiologically relevant to several major diseases including diabetes and certain cancers. RAGE inhibition has been reported to reduce morbidity in these disease states. However, to design better RAGE inhibitors it is necessary to understand the structural basis behind the RAGE-ligand interaction and currently this is not well understood. This thesis focuses on understanding the interaction of RAGE with two of its ligands; AGEs and S100B.;AGEs are highly heterogeneous and are formed as a result of non-enzymatic glycation. A panel of AGEs were characterized in terms of their side chain modifications, thermal stability, secondary structure, aggregation and surface charge. These glycation induced changes were then correlated to RAGE binding.;Building on these results the role of AGE-RAGE interaction in pancreatic cancer cell proliferation and migration was determined. Ribose modified BSA induced ROS formation, which then triggered NF-kappaB upregulation via RAGE induced ROS signaling. Ribose BSA increased pancreatic cell proliferation and migration. Anti-RAGE antibodies and RAGE inhibitors prevented AGE induced cellular effects. The role of ribose modified BSA was also determined in macrophage activation and pro-inflammatory cytokine release. Rapid internalization was observed of the ribose-BSA and confocal imaging revealed the internalization of the AGE compound into the lysosomes which lead to the ROS production, NF-kappaB activation and pro-inflammatory cytokine release in a RAGE independent signaling mechanism.;Finally, the role of tryptophan residues of the V domain in domain stability and S100B binding was determined. We have generated single, double and triple tryptophan mutants of the V domain by site directed mutagenesis. The effect of Trp residues in the domain stability could not elucidated as no change was observed in the secondary structure of the mutants when compared to the wild type suggesting the plasticity of the V-domain. The fluorescence emission and life time properties of each Trp residue was determined. Our binding assays of the Trp → Ala mutants indicate tighter binding of the S100B to the mutants. The S100-RAGE peptide structures suggest multi modal interaction of S100B-RAGE interaction.