Engineered EV-mediated delivery of an anti-amyloid peptide provides neuroprotection in an in vitro Alzheimer's disease model.

Alzheimer's disease is driven in part by amyloid-β (Aβ) aggregation, oxidative stress, and progressive neuronal dysfunction. Despite various attempts, therapeutic translation remains limited by inefficient delivery of bioactive molecules to neuronal cells. This study presents a surface-engineered extracellular vesicle (EV) platform designed for targeted peptide delivery, assessing its neuroprotective efficacy in an in vitro model of Alzheimer's disease. EVs were obtained from NIH/3T3 cells expressing Lamp2b-RVG and were surface-modified with the β-sheet breaker peptide H102 through CP05-CD63 affinity binding. ATR-FTIR, SERS Raman spectroscopy, high-resolution transmission electron microscopy, nanoparticle tracking analysis, zeta potential measurements, and EV marker profiling demonstrated successful peptide conjugation and vesicle integrity. Aggregated Aβ25-35 was utilized to assess neuronal toxicity in NGF-differentiated PC-12 cells. Peptide-modified EV demonstrated effective, time-dependent cellular uptake and significantly improved cell viability while decreasing membrane damage and intracellular reactive oxygen species levels in comparison to Aβ-treated controls. Treatment with Peptide-modified EV normalized the expression of key genes associated with Alzheimer's, such as APP, Bax, Sirt1, and Stat1, suggesting a coordinated modulation of amyloidogenic, apoptotic, oxidative, and inflammatory pathways. The results indicate that surface-engineered EVs facilitate efficient neuronal delivery of therapeutic peptides and offer multi-level cytoprotection against Aβ-induced neurotoxicity. This study emphasizes the capability of peptide-decorated EV as a multifunctional nanocarrier system for the treatment of Alzheimer's disease.