PSEN1 and Alzheimer disease: Because selenium supplementation was shown to improve insulin homeostasis in AD patients and to exert neuroprotective effects in a mouse model of AD (Sridhar, 2015; Van Der Jeugd et al., 2018; Tamtaji et al., 2019), we performed label-free LC–MS/MS quantitative proteomics to identify DEPs in the hippocampus and cerebral cortex of APP/PS1 mice—an AD animal model—following 2 months of treatment with sodium selenate.