Glyceryl tribenzoate, a flavoring agent, stimulates hippocampal plasticity and protects memory via PPARα

Glyceryl tribenzoate (GTB) or tribenzoin is a flavoring agent with characteristic anti-microbial property. We have already delineated GTB's immunomodulatory role via the enrichment of regulatory T cells in mouse models of multiple sclerosis and anti-neuroinflammatory role via the reduction of glial activation in a monkey model of Parkinson's disease and a mouse model of Huntington's disease. However, its role has never been explored in Alzheimer's disease (AD), the most common neurodegenerative disorder in human. This study underlines the importance of GTB in promoting the growth and function of hippocampal neurons via upregulation of plasticity-associated genes, enrichment of dendritic spines and stimulation of inotropic calcium influx. Accordingly, oral GTB improved hippocampal plasticity and protected memory and learning in 5xFAD mice. Similarly, GTB treatment also reduced cerebral plaque load and increased the life span of aged 5xFAD mice. Interestingly, we observed that peroxisome proliferator-activated receptor alpha (PPARα), a nuclear hormone receptor, served as a receptor of GTB. Consequently, GTB was shown to improve hippocampal plasticity and increase cognitive functions in 5xFAD, but not 5xFAD/Ppara-null, mice, indicating an important role of PPARα in GTB-mediated neuroprotection. These results suggest that oral GTB may have therapeutic importance for improving hippocampal functions in AD patients.