Therapeutic potential and underlying mechanisms of engineered young plasma-derived exosomes in Alzheimer's disease.

Exosomes (EXOs) derived from the plasma of young individuals are believed to have the potential to ameliorate aging-related memory deficits. However, their specific roles and mechanisms in Alzheimer's disease (AD) therapy have not yet been systematically investigated. In this study, the rabies virus glycoprotein-targeting peptide (RVG-29) was conjugated to the surface of young plasma-derived EXOs to construct RVG-engineered EXOs (RVG-EXOs), and their therapeutic potential and underlying mechanisms in AD models were systematically evaluated. In 3×Tg AD model mice, exogenous administration of young plasma-derived EXOs and their engineered product (RVG-EXOs) revealed that RVG-EXOs could more efficiently enter brain tissue and target neurons, significantly reduce Aβ plaque and phosphorylated Tau (P-Tau) pathological deposition, restore synaptic structure, promote neuronal survival, and improve cognitive behavior. Mechanistic studies demonstrated that RVG-EXOs inhibited RPTOR expression, thereby activating the autophagy pathway and promoting the clearance of pathological proteins. Both in vitro and in vivo experiments confirmed that overexpression of RPTOR significantly suppressed the therapeutic effects of RVG-EXOs. single-cell transcriptomic profiling further revealed that RVG-EXOs not only increased neuronal proportion and modulated excitatory/inhibitory neuronal balance but also reshaped the microglial landscape by reducing deleterious disease-associated while increasing homeostatic surveillant microglia. In summary, this study not only reveals for the first time the potential value of young plasma-derived EXOs in AD treatment but also, through RVG engineering strategies and the elucidation of the RPTOR-autophagy mechanism, provides new insights for targeted therapy of neurodegenerative diseases.