INS-1, MIN-6, HeLa and EA.hy926 cells, treated or not with siRNA against presenilin-1 or GSK3β inhibitor CHIR99021, were plated in XF96 polystyrene cell culture microplates (Seahorse Bioscience) at a density of 60.000 cells/well for HeLa and EA.hy926, 120.000 cells/well for MIN-6 and 140.000 cells/well for INS-1 cells. After overnight incubation, mitochondrial respiration was performed using an XF96 extracellular flux analyzer (Seahorse Bioscience®) as previously described [21 (link)]. Oxygen consumption was normalized to protein content (pmol O2/min × μg protein).