APP and Alzheimer disease: Immunofluorescence staining with antibodies to pan-lysine-succinylation and to Aβ oligomers (NU-4)36 or Aβ plaques (β-Amyloid, D3D2N) showed an early increase in lysine succinylation that appeared to parallel oligomer accumulation (Fig. 5c and Supplementary Fig. 3a) in the hippocampus of a transgenic mouse model of AD (Tg19959 mice), which carries the human APP with two pathogenic familial AD mutations.