Alpha-Ketoglutarate Ameliorates Synaptic Plasticity Deficits in APP/PS1 Mice Model of Alzheimer's Disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disorders, characterized by a progressive decline in cognitive function. Increasing evidence indicates that alpha-ketoglutarate (AKG), a key metabolite in the tricarboxylic acid (TCA) cycle, can extend lifespan and healthspan across various animal models, raising interest in its potential neuroprotective effects in age-related disorders such as AD. Our previous research found that dietary supplementation with calcium alpha-ketoglutarate (CaAKG), a calcium derivative of AKG, enhances both lifespan and healthspan in mice. However, little is known about the neuroprotective role of AKG/CaAKG in AD. Here, we show that CaAKG could rescue synaptic deficits that are associated with AD. Treatment with AKG or CaAKG ameliorates long-term potentiation (LTP) at hippocampal CA1 synapses in APP/PS1 mice, with a more profound effect in female AD mice than in males. The effects of CaAKG were mediated through an NMDA receptor-independent mechanism involving L-type calcium channels (LTCC) and calcium-permeable AMPA receptors (CP-AMPARs). Analysis of protein expression showed that AD hippocampal slices treated with CaAKG exhibited increased LC3-II levels, indicating enhanced autophagy. Similarly, rapamycin, an mTOR inhibitor, also rescued LTP deficits in AD mice, suggesting that the observed increase in autophagy may contribute to neuroprotection. Interestingly, rapamycin showed differential effects, as it rescued LTP in AD mice but blocked LTP in WT mice. We also observed that CaAKG facilitated synaptic tagging and capture (STC), a widely studied cellular model for associative memory, indicating its potential to facilitate associative memory. Overall, our findings suggest that CaAKG has neuroprotective effects in APP/PS1 mice. We propose CaAKG as a promising therapeutic target not only for aging but also for AD and potentially other age-associated neurodegenerative diseases, highlighting geroprotective strategies as viable alternatives for the prevention and treatment of AD.