Hippocampal Proteomic Alteration in Triple Transgenic Mouse Model of Alzheimer’s Disease and Implication of PINK 1 Regulation in Donepezil Treatment

Abstract

Donepezil is a clinically approved acetylcholinesterase inhibitor (AChEI) for cognitive improvement in Alzheimer’s disease (AD). Donepezil has been used as a first-line agent for the symptomatic treatment of AD, but its ability to modify disease pathology and underlying mechanisms is not clear. We investigated the protective effects and underlying mechanisms of donepezil in AD-related triple transgenic (APPSwe/PSEN1M146V/MAPTP301L) mouse model (3×Tg-AD). Mice (8-month old) were treated with donepezil (1.3 mg/kg) for 4 months and evaluated by behavioral tests for assessment of cognitive functions, and the hippocampal tissues were examined by protein analysis and quantitative proteomics. Behavioral tests showed that donepezil significantly improved the cognitive capabilities of 3×Tg-AD mice. The levels of soluble and insoluble amyloid beta proteins (Aβ1–40 and Aβ1–42) and senile plaques were reduced in the hippocampus. Golgi staining of the hippocampus showed that donepezil prevented dendritic spine loss in hippocampal neurons of 3×Tg-AD mice. Proteomic studies of the hippocampal tissues identified 3131 proteins with altered expression related to AD pathology, of which 262 could be significantly reversed with donepezil treatment. Bioinformatics with functional analysis and protein–protein interaction (PPI) network mapping showed that donepezil significantly elevated the protein levels of PINK 1, NFASC, MYLK2, and NRAS in the hippocampus, and modulated the biological pathways of axon guidance, mitophagy, mTOR, and MAPK signaling. The substantial upregulation of PINK 1 with donepezil was further verified by Western blotting. Donepezil exhibited neuroprotective effects via multiple mechanisms. In particular, PINK 1 is related to mitophagy and cellular protection from mitochondrial dysfunction, which might play important roles in AD pathogenesis and represent a potential therapeutic target.

Memantine Improves Cognitive Function and Alters Hippocampal and Cortical Proteome in Triple Transgenic Mouse Model of Alzheimer's Disease

“…The step-down passive avoidance (SDA) test was performed according to the protocol described in our previous study [18]. Briefly, at training day, a single mouse was gently located on the grid floor, at the same time as electrical stimulation (36 V) was delivered through the grid floor for 5 min.…”

“…The novel object recognition (NOR) test was performed according to the protocol described in our previous study [18]. Briefly, the single mouse was placed to the open-field arena containing two indistinguishable objects (A+A) and allowed to tour for 5 min once daily for 3 days.…”

“…Morris water maze (MWM) test was performed according to the protocol described in our previous study [18]. During training period, platform was located in the same position (one of four quadrants of the pool), and the mouse was placed into the pool facing the wall at one of the four start positions, and its movement was tracked by digital tracking system.…”

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“…The method was referenced to a previous report. 21,22 2.8 Western-blot Reference experimental method 2.4 protein sample preparation. Protein samples were combined with loading buffer (Thermo Fisher Scientic) and heated at 96 C for 8 minutes, then separated on 10% SDS-PAGE and transferred to PVDF membrane.…”