TP53 and Alzheimer disease: SIRT1 deacetylates histones H1 (Lys26), H3 (Lys9 and 14), and H4 (Lys16) [91], and deacetylation of other SIRT1 substrates (e.g., p53, FOXO1-FOXO4) is known to protect against neurodegeneration in mouse models of AD [92,93].