SIRT1 and Alzheimer disease: Notably, TSG-dependent sir-2.1-mediated protection of mitochondrial function not only prolonged the lifespan of wild-type worms but also inhibited the Aβ toxicity of AD nematodes, which is consistent with a study showing that the knockout of the SIRT1 protein induces neurodegenerative diseases in aging mice, while the overexpression of the SIRT1 protein effectively reduced the formation of amyloid plaques and improved the behavioral phenotype [32].