PPIB and Alzheimer disease: Indeed, in some neurodegenerative disorders such as AD or PD, different studies have shown the presence of neurofibrillary tangles, β-amyloid deposits, or Lewy neurites in the ONs (Talamo et al., 1989, 1991; Trojanowski et al., 1991; Lee et al., 1993; Crino et al., 1995; Funabe et al., 2013; Saito et al., 2016).