Correction of mTORC1‐mediated brain protein synthesis rescues memory in mouse models of Alzheimer’s disease

Abstract

AbstractBackgroundAlzheimer’s disease (AD) is a neurodegenerative disorder characterized by synapse failure and cognitive decline. Brain mRNA translation is central to synaptic plasticity and cognition, and converging evidence indicates it is impaired in AD. The mammalian target of rapamycin complex 1 (mTORC1) pathway plays a key role in regulating protein synthesis, and mTORC1 signaling has received considerable attention in AD research. In this current work, we investigated whether stimulating mTORC1‐mediated protein synthesis can alleviate the impairments in synaptic plasticity and memory in AD mice.MethodTo address this question, we used two different approaches: 1. genetic reduction of the translational repressors, Fragile X messenger ribonucleoprotein (FMRP) or eukaryotic initiation factor 4E (eIF4E)‐binding protein 2 (4E‐BP2); and 2. pharmacological treatment with (2R,6R)‐hydroxynorketamine (HNK), an active metabolite of the antidepressant ketamine that stimulates mTORC1 signaling.ResultOur results showed that genetic reduction of FMRP and 4E‐BP2 prevented the inhibition of hippocampal protein synthesis and memory impairment induced by amyloid‐β oligomers (AβOs) in mice. Reduction of 4E‐BP2 further rescued memory deficits in the APPswe/PS1dE9 (APP/PS1) transgenic mouse model of AD. Moreover, HNK treatment prevented deficits in long‐term potentiation (LTP) and fear memory in AbO‐infused and APP/PS1 mice.ConclusionTaken together, our findings indicate that strategies targeting mRNA translation correct hippocampal protein synthesis, synaptic plasticity and memory deficits in AD models, and raise the prospect that HNK could emerge as a therapeutic approach in AD.