A novel gentiopicroside derivative clears phosphorylation tau to improve memory of AD mice by targeting AMPK and increase of gut neuroprotective metabolites.

Abstract

BACKGROUND: Gentiopicroside (GPS) was isolated from the traditional Chinese medicine Gentiana rigescens Franch, normally called as Long Dan. The anti-aging activity of GPS and the anti-AD effects of 2H-GPS, a reduced derivative of GPS have been reported previously. PURPOSE: In this study, 2H-GPSE was designed to optimize the structure and improve its bioavailability and bioactivity. Moreover, the aging-induced AD mice were used to identify the target protein of 2H-GPSE and elucidate its mechanism of action. METHODS AND RESULTS: 2H-GPSE exerts its anti-AD effects through two different mechanisms. Western Blot, CETSA, DARTS and SPR were used to explore the targets of 2H-GPSE, and the results showed that 2H-GPSE directly targeted the α, β, and γ subunits of AMP-activated protein kinase (AMPK) and activated the AMPK-SIRT1-FoxO3A signaling pathway. And then, 16S rRNA gene amplicon sequencing analysis of fecal samples revealed that it acts on the brain-gut axis to regulate the levels of indole metabolites in the gut microbiota, including 3-indollepropionic acid (IPA), 3-indollemethanol (I3C), and 3-indoleacetic acid (3IA). In addition, Tau and Aβ proteins aggregates are characteristic of AD, and by visualizing and quantifying tau deposition and Aβ expression using PET and western blot, the results showed that 2H-GPSE was superior to donepezil (DON) for Tau and Aβ clearance. CONCLUSION: These findings demonstrate that the anti-AD effect of 2H-GPSE is achieved through a combination of activation of the AMPK-SIRT1-FoxO3A signaling pathway, neuroprotection and acting on the brain-gut axis, laying an important foundation for its development as an anti-AD agent.