Hif 1α

At 70~75% confluency, astrocytes were transfected with small interfering ribonucleic acid (si-RNA) against a negative control (Thermo Fisher Scientific) or SIRT1, SIRT2, SIRT3, SIRT4, SIRT5, nicotinamide phosphoribosyltransferase (Nampt), ERRα, Tom20, Tom22, PHD2 (Santa Cruz Biotechnology), and HIF-1α (Dharmacon, Lafayette, CO, USA) using RNAiMax (Thermo Fisher Scientific). We used 50 nM si-RNAs except for si-PHD2 (10 nM). After approximately 16 h of recovery, the cells were incubated with KRGE (0.5 mg/mL) or water for 24 h in DMEM without FBS.

The human neuroblastoma cell line SK-N-MC was obtained from Korean Cell Line Bank (Seoul, Korea). The antibodies of p-Akt (Thr308), p-Akt (Ser473), Akt, mTOR, Caveolin-1, Flotillin-2, p-Tau (Ser396), Tau, p-NF-κB p65 (Ser536), NF-κB p65, Lamin A/C, CBP and β-actin were purchased from Santa Cruz Biotechnology (Santa Cruz, CA, USA). The antibodies of p-mTOR (Ser2448), p-p70S6K1 (Thr389) and p70S6K1, were acquired from Cell Signaling Technology (Beverly, MA, USA). Aβ, BACE1, HIF-1α and GPR40 antibodies were obtained from Abcam (Cambridge, MA, USA). The C99 antibody was purchased from EMD Millipore (Darmstadt, Germany). Horse radish peroxidase (HRP)-conjugated IgG was obtained from Jackson Immunoresearch (West Groove, PA, USA). PA, BSA, GW9508, ionomycin, PF4708671, LY294002 and rapamycin were purchased from Sigma Chemical Company (St. Louis, MO, USA). The Akt inhibitor, GW1100 and SN50 used here were purchased from Calbiochem (La Jolla, CA, USA). siRNAs for GPR40, GPR120, APP, BACE1, HIF-1α and non-targeting were obtained from Dharmacon (Lafayette, CO, USA).