Objective

Background. It is not clear how Apolipoprotein E4 (ApoE4), the major genetic risk factor in late onset Alzheimer’s disease (AD), influences AD pathophysiology. Three ApoE isoforms (ApoE2, E3 and E4) exist that just differ in two amino acid sites. These amino acid substitutions are believed to alter ApoE structure and be responsible for ApoE4’s detrimental effects. The hypothesis that a structural difference between ApoE4 and ApoE3 is the cause of the ApoE4-associated increased risk for AD forms the basis of a novel therapeutic approach to modulate ApoE4 structure. Aim. Our aim was develop a set of biophysical assays for the identification of small compounds that interact with ApoE4 and that may modulate its structure. Methodology. We expressed human ApoE4 in E. coli and used purified protein to develop three biophysical assays - Corning® Epic® label free, Microscale Thermophoresis (MST), and Isothermal Titration calorimetry (ITC). We screened the NIH clinical collection against ApoE4 using the Epic® Corning® and further evaluated hits by MST and ITC. Results. Using the Corning® Epic® label free platform, we identified 14 compounds that seem to interact with ApoE4. Our “hit” molecules are currently being evaluated by MST and ITC in the hope the confirmation and subsequent medicinal chemistry optimisation will result in the identification of novel tool compounds that can be used in future studies to investigate ApoE function.