NR promotes PGC-1α responses and BACE1 degradation in the brain. (A) NR-treated primary neuron cultures derived from Tg2576 mice showed increased PGC-1α protein levels probed by Western blot analysis with anti-PGC-1α antibody (Sigma). Values are expressed as mean ± standard error of the mean; n = 3; * p < 0.05, Student t test. (B) BACE1 protein levels are decreased by NR treatment and the decrease was attenuated by PGC-1α-shRNA probed by Western blot analysis with anti-BACE1 antibody (Sigma). Values are expressed as mean ± standard error of the mean; n = 3; * p < 0.05, Student t test. Inset shows the protein of adeno-PGC-1α and PGC-1α-shRNA after infected in neurons. Abbreviations: BACE1, β-secretase; CTR, control; NR, nicotinamide riboside; PGC-1α, peroxisome proliferator-activated receptor-γ coactivator 1α; shRNA, small hairpin RNA.