Native PEG-PLGA Attenuates β-Amyloid Aggregation and Toxicity under In Vitro Conditions

Self-aggregation of amyloid-β (Aβ) peptide plays a key role in the pathogenesis of Alzheimer's disease (AD), the most prevalent cause of dementia affecting the elderly population. The development of an effective treatment for AD pathology remains elusive due to the presence of the blood-brain barrier (BBB) and the heterogeneous nature of disease progression. Recently, we reported that FDA-approved native poly(d,l-lactic-co-glycolic acid) (PLGA) nanoparticles without any conjugated/encapsulated agent can attenuate Aβ aggregation/toxicity in cellular and animal models of AD. Given the limitation associated with the fast clearance of the native PLGA by the reticuloendothelial system (RES), in the present study, we synthesized PEGylated native PLGA nanoparticles (PEG-PLGA-1) to reduce their clearance via the RES and evaluated their effects on Aβ aggregation/toxicity after biochemical and structural characterization. Determined with Thioflavin T kinetic assay, dynamic light scattering and fluorescence imaging, it was revealed that the native PEG-PLGA-1, which exhibits increased stability, not only inhibits the aggregation of Aβ peptides, but also triggers the disassembly of Aβ aggregates. Additionally, we showed that PEG-PLGA-1 are nontoxic and can significantly enhance the viability of mouse primary cortical cultured neurons against Aβ-mediated toxicity. Collectively, these results suggest that native PEG-PLGA-1 nanoparticles can inhibit Aβ aggregation and trigger disassembly of Aβ aggregates and can protect neurons against Aβ-mediated toxicity, thus suggesting their unique therapeutic potential in the treatment of AD pathology.