Two dimensional neurons differentiated for 6–8 weeks were treated with inhibitors. Three dimensional neurons differentiated for 9 weeks were evenly distributed into 6-well plates, and the spheroids were treated either with BACE1 inhibitor LY2886721 at 0.1, 0.5 or 1μM (APEXBT, Boston, MA), or γ-Secretase inhibitor Compound E at 0.1, 0.5 or 1μM (EMD Millipore, Billerica, MA). After 2 days of treatment, the media was collected for Aβ 40 and 42 measurement by Enzyme linked immunosorbent assay (ELISA). For quantification of drug exposure, some spheroids were collected after 2 days of treatment and subjected to LC-MS/MS quantification.
