Mechanism mediating oligomeric Aβ clearance by naïve primary microglia

►Naïve primary microglia internalized oligomeric amyloid-β peptide (oAβ) in a time- and dose-dependent manner. ►Knockdown of scavenger receptor type-A, but not CD36 by small interfering RNAs (siRNAs) attenuated oAβ internalization by primary microglia. ►Lysosomal cysteine protease including cathepsin B, but neither serine nor aspartate proteases, degraded internalized oAβ by primary microglia. ►Epoxomicin, a specific proteasome inhibitor, failed to prevent oAβ degradation in microglia. ►Neprilysin, matrix metalloproteinases, and insulin degrading enzyme were not involved in oAβ degradation in microglia.