Aβ40 and 42 levels were mainly measured by Human/Rat Aβ ELISA Kit from Wako (Osaka, Japan). The conditioned media from undifferentiated or differentiated ReN cells were collected and diluted by 1:10 or 1:100 with a dilution buffer provided by the company. Synergy 2 ELISA plate reader (BioTek, Winooski, VT, USA) was used to quantify Aβ40 and 42 ELISA signal. To simultaneously measure Aβ38, Aβ40 and Aβ42 levels, a multi-array electrochemiluminescence ELISA kit was used (Meso Scale Discovery, Rockville, MD, USA).
