G82S RAGE polymorphism influences amyloid-RAGE interactions relevant in Alzheimer’s disease pathology

Abstract

Receptor for advanced glycation end products (RAGE) has been implicated in the pathophysiology of Alzheimers disease(AD) due to its ability to bind amyloid-beta (Aβ42) and mediate inflammatory response. G82S RAGE polymorphism is associated with AD but the molecular mechanism for this association is not understood. Our previous in silico study indicated a higher binding affinity for mutated G82S RAGE, which could be caused due to changes in N linked glycosylation at residue N81. To confirm this hypothesis, in the present study molecular dynamics (MD) simulations were used to simulate the wild type (WT) and G82S glycosylated structures of RAGE to identify the global structural changes and to find the binding efficiency with Aβ42 peptide. Binding pocket analysis of the MD trajectory showed that cavity/binding pocket in mutant G82S glycosylated RAGE variants is more exposed and accessible to external ligands compared to WT RAGE, which can enhance the affinity of RAGE for Aβ. To validate the above concept, an in vitro binding study was carried using SHSY5Y cell line expressing recombinant WT and mutated RAGE variant individually to which HiLyte Fluor labeled Aβ42 was incubated at different concentrations. Saturated binding kinetics method was adopted to determine the K d values for Aβ42 binding to RAGE. The K d value for Aβ42- WT and Aβ42-mutant RAGE binding were 92±40 nM (95% CI-52 to 152nM; R 2 -0.92) and 45±20 nM (95% CI -29 to 64nM; R 2 -0.93), respectively. The K d value of <100nM observed for both variants implicates RAGE as a high-affinity receptor for Aβ42 and mutant RAGE has higher affinity compared to WT. The alteration in binding affinity is responsible for activation of the inflammatory pathway as implicated by enhanced expression of TNFα and IL6 in mutant RAGE expressing cell line which gives a mechanistic view for the G82S RAGE association with AD.

Microglia in Alzheimer’s Disease: A Target for Therapeutic Intervention

“…RAGE blockade leads to reduced microglial migration toward Aβ deposits (Lue et al, 2001 ). More recently, numerous studies have reported the pathogenic role of RAGE in AD progression, which promotes the release of pro-inflammatory mediators by activated microglia (Fang et al, 2010 ; Deane et al, 2012 ; Cathrine C et al, 2020 ). A potent multimodal RAGE blocker effectively inhibited the microglial activation and neuroinflammatory response to Aβ and improved the cognitive performance in AD transgenic mice (Deane et al, 2012 ).…”

Nanopore Sequencing of RAGE Gene Polymorphisms and Their Association with Type 2 Diabetes

“…The non-synonymous replacement of glycine by serine at the 82nd position of RAGE caused by rs2070600 induces changes in the structure of the variable domain of RAGE, which can potentially affect AGE–RAGE signaling. In vitro studies have elucidated that RAGE with rs2070600 has a higher binding affinity for amyloid-beta peptides (Aβ42) and prototypic S100/cangrulin, which upregulated inflammatory mediators. , Substitution of glycine with serine at the 82nd position of RAGE promotes N-linked glycosylation of adjacent asparagine residue at the 81st position, which may also affect ligand binding and further downstream signaling initiated by AGE–RAGE interaction . Several studies have also found a significantly lower plasma sRAGE level in the subjects carrying rs2070600, ,,, and the same has been elucidated using a cell culture model .…”

RAGE engagement by SARS-CoV-2 enables monocyte infection and underlies COVID-19 severity

“…Interestingly, human RAGE is encoded by the AGER gene, which presents multiple single-nucleotide polymorphisms. Different studies have reported a direct link between AGER genetic polymorphisms and the severity of different pathological conditions, including non-alcoholic fatty liver disease, 68 cancer, 69 Alzheimer’s disease, 70 and cardiovascular disorders. 71 A direct contribution of these comorbidities to the RAGE expression levels cannot be excluded.…”