Gallein-Loaded Albumin Nanoparticles Prevent Amyloid-β-Induced Amyloidogenic APP Processing, Synaptic Loss, and Dendritic Pathology.

Alzheimer's disease (AD) is a multifactorial and highly debilitating disorder with a long clinical course. The development of new therapeutic strategies capable of mitigating or delaying disease progression remains a major challenge. We previously identified the amyloid precursor protein (APP) as a receptor for aggregated amyloid-β (Aβ) species that signals through a Go/Gβγ-dependent pathway, thereby promoting amyloidogenesis and neurotoxicity. In this context, gallein (GAL), a selective inhibitor of Gβγ signaling, has demonstrated robust neuroprotective effects in preclinical AD models. However, GAL exhibits poor stability and limited aqueous solubility, which may restrict brain bioavailability. To overcome these limitations, a nanotechnology-based formulation strategy was implemented. Here, we report the design and generation of human serum albumin-based nanoparticles (HSA NPs) loaded with GAL (NP-GAL) using a green desolvation method followed by thermal stabilization. Using murine neuroblastoma cells, primary rat cortical neurons, and human iPSC-derived neurons, we demonstrate that NP-GAL effectively prevents Aβ-induced amyloidogenic APP processing, dendritic dystrophy, and presynaptic loss. In addition, both empty NPs and NP-GAL exhibit association with Aβ aggregates, suggesting an additional benefit, as these nanoparticles mitigate amyloid-associated toxicity. Notably, the nanoparticles themselves exert beneficial effects on dendritic morphology and provide protection against neurotoxic insults beyond amyloid pathology, including those induced by rotenone, a widely used experimental model of Parkinson's disease. Together, these in vitro findings suggest that HSA-based nanoparticles hold potential as a platform to stabilize GAL and exert intrinsic neuroprotective effects. These results provide a proof-of-concept for exploring nanoparticle-mediated Gβγ inhibition to counteract Aβ-induced neuronal dysfunction and synaptic pathology.