APP and Alzheimer disease: Sortilin may involve in mood disorders (Buttenschøn et al., 2015; Devader et al., 2017; Moreno et al., 2018), and in brain aging and Alzheimer’s disease (AD) pathogenesis by interplaying with β-amyloid precursor protein (APP), β-secretase-1 (BACE1) and tau (Finan et al., 2011; Gustafsen et al., 2013; Yang et al., 2013; Andersson et al., 2016; Johnson et al., 2017; Xu et al., 2018).